if remote server sends malicious response.

We need to check if the SHOW TABLE STATUS query we issue inside the
FEDERATED engine returned the result with the proper (or just sufficient)
number of rows. Otherwise statements like row[12] can crash the server.


sql/ha_federated.cc:
  bug #29801 Federated engine crashes local server
                 if remote server sends malicious response.
  
  Return with the error if the remote server return fewer rows than we need.