Fix totalDiskSpaceUsed calculation

patch by yukim; reviewed by krummas for CASSANDRA-8205
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/io/sstable/SSTableDeletingTask.java
Merge branch 'cassandra-2.1' into trunk
cqlsh: upgrade bundled python driver to 2.1.2

Patch by Tyler Hobbs for CASSANDRA-8031
Merge branch 'cassandra-2.1' into trunk
Fix merge on test
Merge branch 'cassandra-2.1' into trunk
fix test, take 2
Merge branch 'cassandra-2.1' into trunk
add jmxPort to stress args (ninja)
Merge branch 'cassandra-2.1' into trunk
fix stupid compile bug
Merge remote-tracking branch 'origin/trunk' into 7813-udf-keyspace