check: set failure status before exit

check: set failure status before exit

check has trapped 'exit 1' and exit with $status, but check always
returns 0 on error because status never gets updated. This causes
problems while running some tests in a loop until it fails, e.g.

	while ./check generic/081; do : ; done

Just set status to 1 before exit, as what we do in the tests.

Also remove an unused $flag while we're at it.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>