tests: fix parallel tests

tests: fix parallel tests

Parallel tests require:

 - the % wildcard to be in a token enclosed by backticks, not single
   quotes

 - that the user still be able to use 'test_patchwork' (so we don't want
   the \_ before the %)

Presumably this was skipped because if you get permissions working
manually but you miss part of the required permissions in the automated
script, you need to delete the old db data in order to observe the
issue.

Amusingly postgres worked the whole time.

Fixes: 6025f0e2533f ("Add parallel testing")
Signed-off-by: Daniel Axtens <dja@axtens.net>