revert previous change so voicemail length check works

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@10205 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/switch_core_file.c

@@ -285,8 +285,6 @@ SWITCH_DECLARE(switch_status_t) switch_core_file_close(switch_file_handle_t *fh)
 		switch_core_destroy_memory_pool(&fh->memory_pool);
 	}
 
-	memset(fh, 0, sizeof(*fh));
-
 	return status;
 }