SERVER-15686 remove unneeded blacklist code and tests from RangeDeleter
SERVER-15750 Break deadlock cycle by not holding the global lock while acquiring the bgsync mutex.
SERVER-15747 stepdown for the lease time after failed election
SERVER-15711: DurThread is at front of queue, but times out
SERVER-15706 Refactor internal user authentication
SERVER-15761 Acquire collection-level lock for getting TTL indexes.

Also need to check that the CollectionCatalogEntry is non-NULL
since the specified namespace may not be found in the catalog.
Merge remote-tracking branch 'root/master'