This should fix Mantis Issue #461.

innodb.test, innodb.result, innodb-index.test, innodb-index.result:
Adjust the test result and mention that the introduced restriction
has been reported as MySQL Bug #51451.

innobase_check_index_keys(): Add a parameter for the InnoDB table and
check that no duplicate index name is added.  Report errors by
my_error() instead of sql_print_error().

rb://260 approved by Sunny Bains