BabuDB/Java/replication:

- TimeDriftDetector no longer crashes the service when a drift was detected. Instead, it's logging it only.
- Fixed a problem when the replication plugin did hang at shutdown.

git-svn-id: https://babudb.googlecode.com/svn/trunk@622 d4c7dd96-b7b2-11dd-893d-d98698f66bbf