Fix NPE in StreamTransferTask.createMessageForRetry()

patch by Josh McKenzie; reviewed by Aleksey Yeschenko for CASSANDRA-7323
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1' into trunk
make Shuffle client static
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Upgrade to Pig 0.12.1

Patch by brandonwilliams for CASSANDRA-6556
Merge branch 'cassandra-2.1' into trunk
fix cast guard to be of the c* FutureTask type
Merge branch 'cassandra-2.1' into trunk
use long math for long results
Merge branch 'cassandra-2.1' into trunk
Make StreamSession#closeSession() idempotent

Patch by JoshuaMcKenzie; reviewed by marcuse for CASSANDRA-7262
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
Merge branch 'cassandra-2.1' into trunk
applying v1 patch
Adding new interface
cleaning up after rebase
remove defunct convict from StreamSession