metadata"
            
Improved error handling such that queries against Information_Schema.Tables won't
fail if a federated table can't make a remote connection.

mysql-test/r/merge.result:
  Updated with warnings that were previously masked.
mysql-test/r/show_check.result:
  Updated with warnings that were previously masked.
mysql-test/r/view.result:
  Updated with warnings that were previously masked.
sql/sql_show.cc:
  If get_schema_tables_record() encounters an error, push a warning,
  set the TABLE COMMENT column with the error text, and clear the
  error so that the operation can continue.