pypa/pip — pull request #2181 by dacjames (2014-12-13 00:31:27+00:00)
Title: update submodules after checkout

Prior to this fix the git submodule feature and the git version feature did not play nicely together. Specifically, if you run `pip install git+https://some.repo@some-branch` where `some-branch` includes submodules but `master` does not, the submodules will not be updated.

To fix, just update_submodules after the rev check.