Force batchlog replay before decommissioning a node

patch by Branimir Lambov; reviewed by Aleksey Yeschenko for
CASSANDRA-7446
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/BatchlogManager.java
Merge branch 'cassandra-2.1' into trunk