Fix infinite loop on exception while streaming

Patch by JoshuaMcKenzie; reviewed by marcuse for CASSANDRA-7330
Merge branch 'cassandra-2.0' into cassandra-2.1
Merge branch 'cassandra-2.1' into trunk
Make sure we clear out repair sessions from netstats

Patch by JoshuaMcKenzie; reviewed by marcuse for CASSANDRA-7329
Merge branch 'cassandra-2.1' into trunk
Don't fail streams on failure detector downs

Patch by JoshuaMcKenzie; reviewed by marcuse for CASSANDRA-3569
Merge branch 'cassandra-2.1' into trunk