Fix cf name extraction from manifest in Directories.migrateFile()

patch by Marcus Eriksson; reviewed by Aleksey Yeschenko for
CASSANDRA-5242
Merge branch 'cassandra-1.1' into cassandra-1.2

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/db/Directories.java
Merge branch 'cassandra-1.2' into trunk