[tests] Fix test_daemon to not abort the rest of the test suite
[tests] Fix test_daemon to not abort the rest of the test suite

If we do not fork within the test where we daemonize, the current
process will get daemonize and the test suite will stop.

fmoo/sparts,facebook/sparts,fmoo/sparts,facebook/sparts,djipko/sparts,djipko/sparts