Code review comment for lp:~corey.bryant/charm-helpers/swift-mitaka

The code changes in this mp only target the swift paths so it should have no impact on non-swift charms.

I've tested this code with swift-proxy and swift-storage deploys on icehouse and mitaka-proposed, in addition to upgrades from icehouse->juno->kilo->liberty. Note that an attempt to upgrade from liberty->mitaka remains at the liberty version of swift. I think this makes sense since liberty and mitaka both have 2.5.0 at the moment.