Hide warning about sometimes initialized variable

The rc variable here was always initialized but the compiler couldn't
see that because of the lack of an unconditional else clause.

src/mod/applications/mod_memcache/mod_memcache.c

@@ -230,7 +230,7 @@ SWITCH_STANDARD_API(memcache_function)
 	uint32_t flags = 0;
 	unsigned int server_count = 0;
 
-	memcached_return rc;
+	memcached_return rc = 0;
 	memcached_st *memcached = NULL;
 	memcached_stat_st *stat = NULL;