BUILD: report commit ID in git versions as well

BUILD: report commit ID in git versions as well

Currently, the commit ID appears in the sub-version in snapshots, but
when people use the git repository, we only have the commits count,
and not the last commit ID, which requires to count commits when
troubleshooting. This change ensures that unreleased versions also
report the commit ID before the commit number, such as :

      1.6-dev0-bbfd1a-50

Tagged versions will not have this, since the post-release commit count
is zero.