Common setup functions do not work when used in a git submodule

[Robert Myers]

There are several functions in the common setup that check for the existence of a directory named '.git'. This fails when the project added as a git submodule. When a submodule is created the '.git' is actually a file that points to the correct location of the submodule .git folder like this 'gitdir: ../.git/modules/nova', ie. the parent repository .git folder.

The check should change from:

os.path.isdir('.git')

to:

os.path.exists('.git')

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/22055

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/22067

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/22067
Committed: http://github.com/openstack/oslo-incubator/commit/8ce59472653439d646309395bf195ec6163ff29a
Submitter: Jenkins
Branch: master

commit 8ce59472653439d646309395bf195ec6163ff29a
Author: Robert Myers <email address hidden>
Date: Fri Feb 15 14:32:07 2013 -0600

    Change the check for the existence of .git directory.

    In common setup the check for the .git directory is too
    restrictive. Instead of checking that it is a directory just
    check to see if it exists. That way if the project is part
    of a submodule it will continue to work correctly.

    Change-Id: If6b6531ab5778ac17537e3f18bde1844620c8316
    Fixes: bug 1126416