Removed old parent delegating code in StoreStats which would cause double counting.

Conflicts:
	src/java/voldemort/store/stats/StoreStats.java
Merge branch 'master' of https://github.com/voldemort/voldemort
Merge Read and Write Quota

Combined GET and GETALL to GET
Combined PUT and DELETE to PUT
It would be cleaner if we rename the new GET to READ and PUT to WRITE
But it might break the backward compatibility so leaving it like this
for now.
Made the read quota take all GET_ALL keys into account
Releasing Voldemort 1.8.15
bdb native backup fixups

1. add message for native backup status
2. add bdb env config param: bdb.recovery.force.checkpoint