Bad logic clearing exit code

If tests in inc21.30.1 failed, the exit_code was getting cleared
so the test21.30 as a whole never recognized the failure.

testsuite/expect/inc21.30.1

@@ -88,6 +88,4 @@ proc inc21_30_1 {} {
 	# Cancels remaining jobs
 	cancel_job $job_id1
 	cancel_job $job_id2
-
-	set exit_code 0
 }