Description:
------------
In ext/snmp/snmp.c, it is possible to exit php_snmp_internal without closing the snmp session when performing an snmpget. This leads to 'too many open files' errors on a script with many snmpget requests.


Reproduce code:
---------------
ext/snmp/snmp.c: Lines 427 to 430

                    if (st == 1) {
                        *return_value = *snmpval;
                        zval_copy_ctor(return_value);
                        return;

should be changed to:

                    if (st == 1) {
                        *return_value = *snmpval;
                        zval_copy_ctor(return_value);
                        snmp_close(ss);
                        return;


Expected result:
----------------
No more 'too many open files' errors.


Actual result:
--------------
No more 'too many open files' errors.