Description:
------------
A segmentation fault is triggered when the exchange doesn't exists and a message is published.

Reproduce code:
---------------
$ex = new AmqpExchange(new AmqpConnection(), "foo");
$ex->publish("data", "bar");

Expected result:
----------------
An exception, most likely

Actual result:
--------------
Program received signal SIGSEGV, Segmentation fault.
0x0000000000742d84 in zend_object_store_get_object (zobject=0xdc7c80) at /root/compile/php-5.3.2-apache/Zend/zend_objects_API.c:272
272             return EG(objects_store).object_buckets[handle].bucket.obj.object;

(gdb) bt full
#0  0x0000000000742d84 in zend_object_store_get_object (zobject=0xdc7c80) at /root/compile/php-5.3.2-apache/Zend/zend_objects_API.c:272
No locals.
#1  0x0000000082491609 in zim_amqp_exchange_class_publish (ht=14449792, return_value=0xdc92c0, return_value_ptr=0xdb3ca0, this_ptr=0x82493224, return_value_used=14329312) at /tmp/pear/temp/amqp/amqp.c:1627
        str = "??H\202\000\000\000\000\000P?\200\000\000\000\000P????\177\000\000\023\000\000\000\001\000\000\000\001", '\0' <repeats 15 times>, "C\000\000\000\000\000\000\000??H\202\000\000\000\000\001\000\000\000\000\000\000\000??H\202\000\000\000\000\000??\200\000\000\000\000\206L?\200\000\000\000\000p????\177\000\000?????\177\000\000\000P?\200\000\000\000\000\000??\200\000\000\000\000?SY\202\000\000\000\000\001\000\000\000\000\000\000\000?EY\202\000\000\000\000?~?\200\000\000\000\0000?s\000\000\000\000\000\226B?\200\000\000\000\000k?4\202\000\000\000\000\000P?\200\000\000\000\000\200\221?\000\000\000\000\000\001\000\000\000\000"...
        pstr = (char **) 0xdc7c80
        id = (zval *) 0xdc7cb0
        iniArr = (zval *) 0x0
        zdata = (zval **) 0x80cda400
        ctx = (amqp_exchange_object *) 0xdc8f70
        ctx_cnn = (amqp_object *) 0xdc7c50
        key_name = 0xdca950 "bar"
        key_len = 3
        msg = 0xdc92a0 "data"
        msg_len = 4
        parms = 0
        res = {reply_type = AMQP_RESPONSE_SERVER_EXCEPTION, reply = {id = 17330400, decoded = 0x1087040}, library_errno = 320}
        props = {_flags = 17330760, content_type = {len = 2185830691, bytes = 0x1}, content_encoding = {len = 1310761, bytes = 0x0}, headers = {num_entries = 0, entries = 0xdb3d28}, delivery_mode = 16 '\020', priority = 233 '?',
  correlation_id = {len = 17330240, bytes = 0x742c41}, reply_to = {len = 14454673, bytes = 0x7fffffffe910}, expiration = {len = 140737488349456, bytes = 0x3}, message_id = {len = 14368040, bytes = 0x200000202}, timestamp = 7613419,
  type = {len = 140737488349456, bytes = 0x7fffffffe3a8}, user_id = {len = 17330240, bytes = 0x1087248}, app_id = {len = 2186888624, bytes = 0x0}, cluster_id = {len = 0, bytes = 0x3}}
        r = 925149184
#2  0x0000000000745992 in zend_do_fcall_common_helper_SPEC (execute_data=0x1087040) at zend_vm_execute.h:313
        i = 2
        p = (zval **) 0x1087258
        arg_count = 0
        opline = (zend_op *) 0xdc8dc8
        should_change_scope = 1 '\001'
#3  0x0000000000744db9 in execute (op_array=0xdc83a0) at zend_vm_execute.h:104
        ret = 925149184
        execute_data = (zend_execute_data *) 0x1087040
        nested = 1 '\001'
        original_in_execution = 0 '\0'
#4  0x0000000000715ce6 in zend_eval_stringl (str=0xdaa380 "", str_len=0, retval_ptr=0x0, string_name=0xdc83a0 "\004\203?") at /root/compile/php-5.3.2-apache/Zend/zend_execute_API.c:1172
        local_retval_ptr = (zval *) 0x0
        original_return_value_ptr_ptr = (zval **) 0x0
        original_opline_ptr = (zend_op **) 0x0
        orig_interactive = 0
        pv = {value = {lval = 140737488350318, dval = 6.9533558075874774e-310, str = {val = 0x7fffffffec6e "$ex = new AmqpExchange(new AmqpConnection(), \"foo\"); $ex->publish(\"data\", \"bar\");", len = 81}, ht = 0x7fffffffec6e,
    obj = {handle = 4294962286, handlers = 0x51}}, refcount__gc = 1, type = 6 '\006', is_ref__gc = 0 '\0'}
        new_op_array = (zend_op_array *) 0xdc83a0
        original_active_op_array = (zend_op_array *) 0x0
        original_compiler_options = 0
        retval = 0
#5  0x0000000000715ea9 in zend_eval_stringl_ex (str=0xdc7c80 "?\222?", str_len=-2109132252, retval_ptr=0xdb3ca0, string_name=0x7fffffffe20c "\003", handle_exceptions=1) at /root/compile/php-5.3.2-apache/Zend/zend_execute_API.c:1214
        result = 14367904
#6  0x00000000007ac3f2 in main (argc=3, argv=0x7fffffffea80) at /root/compile/php-5.3.2-apache/sapi/cli/php_cli.c:1281
        len = 140737488349824
        argn = (zval *) 0x80cd4680
        input = 0x6e <Error reading address 0x6e: Bad address>
        index = 0
        argi = (zval *) 0x80cd9800
        exit_status = 0
        c = 925149184
        file_handle = {type = ZEND_HANDLE_FP, filename = 0xb77ab2 "-", opened_path = 0x0, handle = {fd = -2109351488, fp = 0x8245d9c0, stream = {handle = 0x8245d9c0, isatty = -2110479536, mmap = {len = 2160804502, pos = 0,
        map = 0x80cda000, buf = 0x7fffffffeaa0 "?????\177", old_handle = 0x3, old_closer = 0x7fffffffea80}, reader = 0x80cb341d <_rtld_bind_start+45>, fsizer = 0x256, closer = 0xffffffff}}, free_filename = 0 '\0'}
        behavior = 6
        reflection_what = 0x0
        orig_optind = 1
        orig_optarg = 0x0
        arg_free = 0x7fffffffec6e "$ex = new AmqpExchange(new AmqpConnection(), \"foo\"); $ex->publish(\"data\", \"bar\");"
        arg_excp = (char **) 0xdc7c80
        script_file = 0x0
        interactive = 0
        module_started = 1
        request_started = 1
        lineno = 0
        exec_direct = 0x7fffffffec6e "$ex = new AmqpExchange(new AmqpConnection(), \"foo\"); $ex->publish(\"data\", \"bar\");"
        exec_run = 0x0
        exec_begin = 0x0
        exec_end = 0x0
        param_error = 0x0
        hide_argv = 0
        ini_entries_len = 110