add auth token to context

As discussed at
http://lists.openstack.org/pipermail/openstack-dev/2014-July/040644.html
SerivceVM project (and other routervm plugins) need auth token in context.
The first user will be l3 routervm plugin.

Closes-Bug: #1343854
Closes-Bug: #1352698
Change-Id: Id5a4c98059894eef33faf19d5ab063780b362f4a
Merge "add auth token to context"