More useful error message for service modification failure  - EUCA-6573

Fixed issue with lost message for Exceptions.error(String).

Updated service modification to exception message is displayed and added
the root cause to the message.

EUCA-6573
Topology threading per component - EUCA-6479

Restored topology threading change but isolated from general component
threads.

EUCA-6479
Merge remote-tracking branch 'origin/dev/sjones/EUCA-6479_threading' into testing
Merge remote-tracking branch 'origin/dev/sjones/EUCA-6573' into testing