Actually test child SIGHUP signal
Actually test child SIGHUP signal

The intention of this test was to wait 5s after sending SIGHUP to a
child process to make sure that it doesn't exit. However, due to a logic
error, it just stopped checking and declared success immediately. Fix
the logic so that we have a better chance of seeing if SIGHUP
incorrectly kills the process.

Change-Id: I1f320a8dfdd7a922b461d070491ad53e6cd2b20d
Related-Bug: #1803731

openstack/oslo.service