Allow git to be defined elsewhere.  This allows for specifici versions to be defined.
Allow a specific version of git to be installed.
Add new default parameter to existing tests so that tests pass.
Add a test for when a git version is specificed.
Merge branch 'gitversion' of https://github.com/brucem/puppet-stash into brucem-gitversion

Conflicts:
	manifests/install.pp
Merge branch 'brucem-gitversion'