DiskLogger: BabuDB can now recover from a broken log. When a corrupted log...

DiskLogger: BabuDB can now recover from a broken log. When a corrupted log entry is encountered while replaying the log on startup, all log entries after the last valid one will be discarded, which brings the database to a consistent state again.

git-svn-id: https://babudb.googlecode.com/svn/trunk@227 d4c7dd96-b7b2-11dd-893d-d98698f66bbf