fix housekeeping code

- the master expiration timer was not really started
- integration issue with the finishStep

@djmitche gave me a copy of state.sqlite of the nine.b.n server

It appears that the problem with nine.buildbot.net is that the master was changed directory, so the name has changed, and it was given another id.
The dangling builds are attached to master 1, which is already inactive. I presume that the housekeepingPR was done after. 

We still need to figure out to cleanup the nine.b.n db. forcing master 1 back to  active will force housekeeping code to run.

I think this would be useful to have some housekeeping commandline tool to automate these kind of tricks.

Please advise in comments
Gah!