Various tblog changes:
Make an attempt to discover what the error was before an swap-* was canceled, if any. Both the main error (canceled) and the other error are stored in the error table. To support this a new column in the error table is added "rank". The primary error has a rank 0 while the other error has a rank 1. Make an attempt to determine when an error is a "me too" error or the real cause of the problem. "Me too" errors are errors which are generally reported when the callie script determined that the caller script fails. The caller script should have reported the error, but in some cases the error didn't make it into the database. Thus if a "me too" is reported as the cause of a "swap-*" more info is needed to determine the true cause. When a "me too" error is reported it is followed by a "..." on it's own line. It is also recorded in the errors table under the new column "need_more_info". Add inferred column to the errors table. This is the same value as the inferred variable in tblog_find_error. Add revision column to errors table to make it easy to tell which algorithm was used to determine the error.