dict_create_add_foreigns_to_dictionary(): Do not commit the transaction.
We want simple rollback in case dict_load_foreigns() would fail.

create_table_info_t::create_table(), row_create_index_for_mysql(),
row_table_add_foreign_constraints(): Before invoking rollback, drop
the table. Rollback would invoke trx_t::evict_table(), and after that
dropping the table would be a no-op.

ha_innobase::create(): Before rollback, drop the table. If the SQL
layer invoked ha_innobase::delete_table() later, it would be a no-op
because the rollback would have invoked trx_t::evict_table().

FIXME: Introduce an undo log record so that the data file would be
deleted on rollback. Also, avoid unnecessary access to the tablespace
during DROP TABLE or the rollback of CREATE TABLE. If the file is going
to be deleted anyway, we should not bother to mark the pages free.