Increase mdsal's notification queue size, make it configurable.

Add System property mdsal.notificationqueue.size to allow tweaking
of queue size.
Increase default queue size from 10 to 1000.

Change-Id: I91e8ac3939092af2b26a7a4d952fe561557b7a46
Signed-off-by: Tomas Olvecky <tolvecky@cisco.com>
Merge "Increase mdsal's notification queue size, make it configurable."