fix nodetool getsstables for blob PK
patch by Nate McCall; reviewed by jbellis for CASSANDRA-6803
merge from 1.2
merge from 2.0
Merge remote-tracking branch 'origin/cassandra-2.1' into cassandra-2.1
Python-driver without a hard dependency on `scales`
Fix leaking validator FH in StreamWriter
patch by Joshua McKenzie; reviewed by jbellis for CASSANDRA-6832
merge from 2.0