Make devref point to official devstack vagrant repo.

Now that we have an official devstack vagrant repo, lets point to that
instead of my own half maintained repo.

Change-Id: I944265d18f6e796608576ea71a7983aed0ece542
docs - fix missing references

Change-Id: Ia33fc8a3495ef6d4b929aa88efccc002616475fc
Merge "Make devref point to official devstack vagrant repo."
Merge "docs - fix missing references"