Description:
------------
When an unconnected mysqli object is var_dump'ed, mysqlnd_ms crashes.

Test script:
---------------
[revin@forge phpugph201407]$ cat master-slave.ini
mysqlnd_ms.enable=1
mysqlnd_ms.force_config_usage = 1
mysqlnd_ms.config_file=/home/revin/git/phpugph201407/mysqlnd_ms_ms.ini
[revin@forge phpugph201407]$ cat mysqlnd_ms_ms.ini
{
  "primary": {
    "master": {
      "master_1": {
        "host": "127.0.0.1",
        "port": "33001"
      }
    },
    "slave": {
    }
  },
  "standby": {
    "master": {
      "master_1": {
        "host": "127.0.0.1",
        "port": "33002"
      }
    },
    "slave": {
    }
  }
}
[revin@forge phpugph201407]$ php -c master-slave.ini -r '$c = mysqli_init(); var_dump($c);'

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1

Warning: var_dump(): Property access is not allowed yet in Command line code on line 1
Segmentation fault

Actual result:
--------------
[revin@forge phpugph201407]$ gdb -ex 'set pagination=0' -batch -quiet -ex 'run -c master-slave.ini -r "\$c = mysqli_init(); var_dump(\$c);"' -ex 'bt full' php|grep 0x000
"on" or "off" expected.
#1  0x00007ffff0c48d6c in mysqlnd_ms_pick_first_master_or_slave (conn=<value optimized out>) at /var/tmp/mysqlnd_ms/mysqlnd_ms_switch.c:547
#2  0x00007ffff0c44947 in php_mysqlnd_ms_get_server_statistics_pub (proxy_conn=0xdb96d0, message=0x7fffffffc710, message_len=0x7fffffffc71c) at /var/tmp/mysqlnd_ms/mysqlnd_ms.c:2075
#3  0x00007ffff0822452 in link_stat_read (obj=0x7ffff7fd4f80, retval=0x7fffffffc768) at /usr/src/debug/php-5.4.30/ext/mysqli/mysqli_prop.c:275
#4  0x00007ffff081c883 in mysqli_read_property (object=0x7ffff7fd37f8, member=0x7fffffffc7d0, type=3, key=0x0) at /usr/src/debug/php-5.4.30/ext/mysqli/mysqli.c:344
#5  0x00007ffff081cb35 in mysqli_object_get_debug_info (object=0x7ffff7fd37f8, is_temp=0x7fffffffc848) at /usr/src/debug/php-5.4.30/ext/mysqli/mysqli.c:473
#6  0x000000000055eb3b in php_var_dump (struc=0x7ffff7f9f158, level=1) at /usr/src/debug/php-5.4.30/ext/standard/var.c:129
#7  0x000000000055ed59 in zif_var_dump (ht=<value optimized out>, return_value=<value optimized out>, return_value_ptr=<value optimized out>, this_ptr=<value optimized out>, return_value_used=<value optimized out>) at /usr/src/debug/php-5.4.30/ext/standard/var.c:183
#8  0x000000000065ee2c in zend_do_fcall_common_helper_SPEC (execute_data=<value optimized out>) at /usr/src/debug/php-5.4.30/Zend/zend_vm_execute.h:643
#9  0x000000000064c768 in execute (op_array=0x7ffff7fd3c68) at /usr/src/debug/php-5.4.30/Zend/zend_vm_execute.h:410
#10 0x00000000005d553e in zend_eval_stringl (str=<value optimized out>, str_len=<value optimized out>, retval_ptr=0x0, string_name=0x6fad69 "Command line code") at /usr/src/debug/php-5.4.30/Zend/zend_execute_API.c:1205
#11 0x00000000005d5619 in zend_eval_stringl_ex (str=<value optimized out>, str_len=<value optimized out>, retval_ptr=<value optimized out>, string_name=<value optimized out>, handle_exceptions=1) at /usr/src/debug/php-5.4.30/Zend/zend_execute_API.c:1252
#12 0x000000000068de84 in do_cli (argc=5, argv=0x7fffffffe128) at /usr/src/debug/php-5.4.30/sapi/cli/php_cli.c:1029
#13 0x000000000068e8a8 in main (argc=5, argv=0x7fffffffe128) at /usr/src/debug/php-5.4.30/sapi/cli/php_cli.c:1365