key deletion: exit status request always threw an exception

- fix it by calling the correct function
6 jobs for 6-verify-md5-checksum in 15 minutes and 20 seconds (queued for 1 minute and 30 seconds)
Status Name Job ID Coverage
  Test
passed py3.5-min-mysql #5515

00:07:31

92.0%
passed py3.5-min-postgresql #5513

00:07:37

92.0%
passed py3.5-min-sqlite #5511

00:05:49

90.0%
passed py3.5-pypi-mysql #5516

00:07:46

92.0%
passed py3.5-pypi-postgresql #5514

00:08:19

92.0%
passed py3.5-pypi-sqlite #5512

00:08:17

91.0%