1.2 nodes show 2.0 nodes as up when upgrading.
Patch by brandonwilliams, reviewed by Tyler Hobbs for CASSANDRA-6554
Don't update system table for unknown nodes/dead states
Patch by Tyler Hobbs, reviewed by brandonwilliams for CASSANDRA-6053
Merge branch 'cassandra-1.2' into cassandra-2.0
Don't update system table for unknown nodes/dead states
Patch by Tyler Hobbs, reviewed by brandonwilliams for CASSANDRA-6053
make isDeadState public
Merge branch 'cassandra-1.2' into cassandra-2.0
fix tests
Revert "fix tests"

This reverts commit fbd51b77a047f2a04a94c4b474881c2be9bf1171.
Initial pass at deferring the release of new sttables until a stream session is complete. CASSANDRA-6503
split FileMessage into two: IncomingFileMessage and OutgoingFileMessage. Also extended StreamMessage.Type
to have both an incoming message serializer and deserializer; needed this to support Type.File having two diff serializers
as java generics would not let me return different subclasses (of FileMessage) from the original FM.Serializer. Hence, needed to
brea it into two serializers, and thus extend SM.Type.
aborting the SSTW when the session closes with a failure state