Record the real messaging version in all cases in OutboundTcpConnection

patch by Aleksey Yeschenko; reviewed by Piotr Kołaczkowski for
CASSANDRA-8057
Don't reset nodes' versions when closing IncomingTcpConnections

patch by Aleksey Yeschenko; reviewed by Marcus Eriksson for
CASSANDRA-7734
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/net/IncomingTcpConnection.java
Merge branch 'cassandra-2.1' into trunk