These messages based on our prep stage during XL
and prints more informative message regarding
drive information.
This change also does a much needed refactoring.
- Instrumentation for locks.
- Detailed test coverage.
- Adding RPC control handler to fetch lock instrumentation.
- RPC control handlers suite tests with a test RPC server.
CBL client does not close connection when the backup process is stopped, this causes
read() on the stream on the server side to block and hence the lock held on the part
is not released. When the backup process is restarted, we again try to lock on the
part and this will block. Using a unique tmp name and not locking it fixes the problem.
