Comment 36 for bug 1571209

Backport of what was applied to zesty plus the fixes discussed here is building in ppa [1]

  * d/libvirt-bin.init, d/libvirt-bin.upstart: fix waiting for the libvirt
    socket (LP: #1571209)
    - avoid timing out on slow systems (only stop when service is stopped)
    - fix whitespace damage formerly added to d/libvirt-bin.init
    - no more sleep without announcing why
    - use incremental sleep to be fast in most fast path cases
    - use incremental sleep to avoid too much repetive messages
    - fix check if unix_sock_dir path is set in /etc/libvirt/libvirtd.conf

I'll test that (so far untested) now and if successful open a merge proposal for team review.
More tests / verifications are welcome.

[1]: https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/2950