Fix git_setup exec and parser.
Fix git_setup exec and parser.

The parser was malformed (expecting positional arguments [no -- in front] yet
also having the 'required' key), the file was lacking a shebang, and the
submodule step was being performed in the wrong directory.

R=iannucci@chromium.org

Review URL: https://chromiumcodereview.appspot.com/15290005

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@201352 0039d316-1c4b-4281-b951-d872f2087c98

luci/recipes-py,shishkander/recipes-py,luci/recipes-py,shishkander/recipes-py