/var/tmp/gitlabhq doesn't need SLOT appended to path

After each upgrade to a new release of gitlabhq. I need to cleanup several !empty directory left from the old release.

The /var/tmp/gitlabhq-${SLOT} is one of those dirs that isn't cleaned up. (/var/log/gitlabhq-${SLOT} is another)

By removing the -${SLOT} from the temp location, this cleanup isn't needed anymore.

I will make a Pull Request for this change:

• I added a check that uses an existing /var/tmp/gitlabhq-${SLOT} when it exists, to prevent that the tmp location changes during a minor update.
  • NOTE: This check can be removed when moving to a new release.
• I also create the tmp/pids folder in the ebuild, obsoleting the gitlabhq-tmpfiles.conf.

I also completed the merge of my previous systemd services change to 9.5 & 10.0