removing dupe const RES_BAD_KEY_PROVIDED

This was causing errors in PHP 7.1. We're sticking with that and
transitioning to 3.x for memcached once PHP 7.1 is fully out

Author: Will Gallego

php_memcached.c

@@ -4390,7 +4390,6 @@ static void php_memc_register_constants(INIT_FUNC_ARGS)
 	REGISTER_MEMC_CLASS_CONST_LONG(RES_MEMORY_ALLOCATION_FAILURE, MEMCACHED_MEMORY_ALLOCATION_FAILURE);
 	REGISTER_MEMC_CLASS_CONST_LONG(RES_CONNECTION_SOCKET_CREATE_FAILURE, MEMCACHED_CONNECTION_SOCKET_CREATE_FAILURE);
 
-	REGISTER_MEMC_CLASS_CONST_LONG(RES_BAD_KEY_PROVIDED,                 MEMCACHED_BAD_KEY_PROVIDED);
 	REGISTER_MEMC_CLASS_CONST_LONG(RES_E2BIG,                            MEMCACHED_E2BIG);
 	REGISTER_MEMC_CLASS_CONST_LONG(RES_KEY_TOO_BIG,                      MEMCACHED_KEY_TOO_BIG);
 	REGISTER_MEMC_CLASS_CONST_LONG(RES_SERVER_TEMPORARILY_DISABLED,      MEMCACHED_SERVER_TEMPORARILY_DISABLED);