Mockproxy check for static methods

Only allow "real" static methods to be mocked via ``WikiaMockProxy::getStaticMethod`` to prevent PHP from segfaulting:

```
#0  zend_check_protected (ce=0xdc5a570, scope=0x4026338) at /build/buildd/php5-5.4.17/Zend/zend_object_handlers.c:970
#1  0x00000000006c9b1d in zend_std_get_method (object_ptr=<optimized out>, method_name=0x408e8c8 "loadOptions", method_len=11, key=0x408ef48)
    at /build/buildd/php5-5.4.17/Zend/zend_object_handlers.c:1068
#2  0x000000000070cdc2 in ZEND_INIT_METHOD_CALL_SPEC_UNUSED_CONST_HANDLER (execute_data=0x7ff479329640)
    at /build/buildd/php5-5.4.17/Zend/zend_vm_execute.h:22334
```

@Wikia/platform-team / @Archbold 

http://qa-s2.wikia-prod:8080/job/phpUnit_trunkAllTests/4968/console