Allow executing CREATE statement multiple times

patch by slebresne; reviewed by jbellis for CASSANDRA-6471
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	CHANGES.txt
Fix infinite loop when paging queries with IN

patch by slebresne; reviewed by iamaleksey for CASSANDRA-6464
Merge branch 'cassandra-2.0' into trunk
Fix merge