[Halld-offline] danarest Crashes / Freezes Running Multithreaded

[Paul Mattione]

Has anyone else noticed crashes & freezes when running the danarest plugin multithreaded on the trunk?  It doesn't always crash or freeze, but when it does it dies early.  Because it's multithreaded it's hard to tell what's causing the problems, but several times now I've seen crashes while threads have been inside:

ccdb::Calibration::GetAssignment
ccdb::SQLiteDataProvider::LoadColumns
ccdb::SQLiteDataProvider::ReadIndex

etc.  Can someone please look into this?  Thanks.  

 - Paul