(Hadoop) allow ACFRW to limit nodes to local DC

patch by Robbie Strickland; reviewed by Aleksey Yeschenko for
CASSANDRA-7252
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/client/RingCache.java
Merge branch 'cassandra-2.0' into cassandra-2.1.0
Merge branch 'cassandra-2.1.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk