- Use "mysql_field_count" to determine if there is a need to
   call "mysql_store_result"


client/mysqltest.c:
  Only call 'mysql_store_result' if 'mysql_field_count' is greater than 0
  indicating that this query has a result set.  This change is mainly since
  if mysql_store_result fails the value returned by mysql_field_count will be reset.