autobuild failure for task source4 during test

[tridge at samba.org]

Hi Volker and Metze,

 > >> I don't think this should be causing an error of
 > >> ERROR: Testsuite[samba4.drs.delete_object.python(vampire_dc)]
 > >> REASON: unable to set up environment vampire_dc - exiting

this is not just a flakey test, it means we have a flakey test setup.

 > I think the failing tests should be added to knownfail or skip
 > (Together with a mail to samba-technical, that someone should fix them),
 > if they prevent such trivial patches from going through.

I think in this case that just disabling one test probably won't help,
as it is a test setup that fails, and other tests will depend on that
test setup. We'd need to disable all tests that use the vampire_dc
environment.

I'll look at it this morning and see if I can fix it properly.

Cheers, Tridge