Fix CQL3 BATCH authorization caching

patch by Aleksey Yeschenko; reviewed by Sylvain Lebresne for CASSANDRA-5145
Merge branch 'cassandra-1.1' into cassandra-1.2

Conflicts:
	src/java/org/apache/cassandra/cql3/statements/BatchStatement.java
Merge branch 'cassandra-1.2' into trunk