Change function and import names for readability

I changed the handle_rbac name to enforce_rbac to reflect what actually
is being done by the decorator.

At the same time, I changed the "con" import that was being aliased from
controllers, to retain its full name, for readability.

Change-Id: I2d81f70b7ccfa3078c9baef2c3ec7d49765b988b
Merge "Change function and import names for readability"