Changed warning display for unknown config, remove tools-url on upgrade, added/modified tests. Bug 1383070.
Clarify comment. Bug 1383070.
Test cleanup as per review. Bug 1383070.
Merge pull request #999 from anastasiamac/Bug1383070-deprecating-tools-stream

Changed warning display for unknown config, remove tools-url on upgrade,...

... added/modified tests. Bug 1383070.
Bug: https://bugs.launchpad.net/juju-core/+bug/1383070

Review: http://reviews.vapour.ws/r/300/