Setting a custom ref in tools/gen-source-tar.sh doesn't work

[Paul Bourke]

It seems using --git-dir to execute commands on a repo different to where you currently are also inexplicably requires --work-tree (https://stackoverflow.com/questions/1386291/git-git-dir-not-working-as-expected)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/202706

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/202706
Committed: https://git.openstack.org/cgit/stackforge/kolla/commit/?id=58678fb2b4e54d275b574a4e57a5b17ff9a820e9
Submitter: Jenkins
Branch: master

commit 58678fb2b4e54d275b574a4e57a5b17ff9a820e9
Author: Paul Bourke <email address hidden>
Date: Thu Jul 16 18:06:13 2015 +0000

    Fix checking out custom refs in gen-source-tar

    It seems using --git-dir to execute commands on a repo different to
    where you currently are also inexplicably requires --work-tree
    (https://stackoverflow.com/questions/1386291/git-git-dir-not-working-as-expected)

    Change-Id: I42806e7d8a169ad9fc1878a0f4e0c03c57beb88b
    Closes-Bug: #1475385