Fix missed use of `git_version` parameter in specs

Pull request #125 removed the ability to specify a git source or revision,
along with other changes; this wasn't reflected in the tests.

This strips out the attempt to use the git version, which wasn't providing any
particular value in any case.

Signed-off-by: Daniel Pittman <daniel@puppetlabs.com>
Merge pull request #126 from daniel-pittman/bug/master/broken-spec-after-125-merged

Fix missed use of `git_version` parameter in specs