LGTM: Use of exit() or quit()

Replace exit() with sys.exit(). exit() or quit() may fail if the interpreter
is run with the -S option.

https://pagure.io/freeipa/issue/7344

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>

ipatests/ipa-test-task

@@ -453,4 +453,4 @@ class TaskRunner(object):
         tasks.add_a_record(master, host)
 
 if __name__ == '__main__':
-    exit(TaskRunner().main(sys.argv[1:]))
+    sys.exit(TaskRunner().main(sys.argv[1:]))