Capture and process salt state return info to output failed states in traceback

[lorengordon]

When a state fails, watchmaker throws a traceback. That traceback is often viewed as and reported as the error message, but it is just indicative of a failed state. The actual failure is in the debug log output, earlier in the log stream. The change proposed here would be to capture the return info of the salt state output and process it, searching for failed states and reporting them in the traceback, to improve the message in the log.