- Added tescases
 - Added handling of HA_ERR_NO_SUCH_TABLE in mysql_rm_table_part2 so that 
   error messages now are consistent


mysql-test/r/ndb_autodiscover.result:
  Added tess for dropping tables that does not exists in engine
mysql-test/t/ndb_autodiscover.test:
  Added tess for dropping tables that does not exists in engine
sql/ha_ndbcluster.cc:
  Updated delete_table and drop_table to retrn HA_ERR_NO_SUCH_TABLE if table was not found in engine.
  Clear error after calling mysql_rm_table_part2 from mysql_find_files
sql/sql_table.cc:
  Added handling of the case when table does not exist in storage engine but on disk as .frm file.