Fix remaining issues with wsrep_sync_wait and query cache.

- Fixes misplaced call to invalidate query cache in
  Rows_log_event::do_apply_event().
  Query cache was invalidated too early, and allowed old
  entries to be inserted to the cache.

- Reset thd->wsrep_sync_wait_gtid on query cache hit.
  THD->cleanup_after_query is not called in such cases,
  and thd->wsrep_sync_wait_gtid remained initialized.