(cherry picked from commit a8bd50f9)

This fixes the uninstall/reinstall oauth-toolkit shenanigans

The dogwood devstack was not compatible with some changes made after dogwood was cut.

Nobody tests on it, and it's probably broken.

When developing on devstack, it's useful to have a way to share source
trees between the host and the guest OS. The src directory is for this
sharing, so that working trees can be accessed inside the guest OS.

First we update ansible then we run the playbook for the devstack.

edX can only support the latest Open edX release, which is Cypress as of
this commit. This commit clears out all the cruft from old Open edX releases
that edX cannot support anyway.

The wiki page [here](https://github.com/edx/configuration/wiki/edX-Developer-Stack#installing-the-edx-developer-stack) says that the minimum Vagrant version is 1.6.5, not 1.5.3.