GitLab

Import code from versioning instead of running update_version.py file.

git-buildpackage expects tags of the form upstream/%(version)s

devflow-bump-version updates the version file that exists at the
toplevel of the git repository and commits the change.

Do not use vim for editing changelog when the mode is snapshot.
Automatically set UNRELEASED distribution to unstable.

Temporary commit: git-dch picks UNRELEASED as debian distribution,
which can not be uploaded to apt repo. Manually edit the file
until fixed.

Import devflow code by
Christos Stavrakakis <cstavr@grnet.gr>,
with minor modifications.