CQL3 shouldn't lowercase DC names for NTS

patch by slebresne; reviewed by jbellis for CASSANDRA-5292
Remove assertion that gossip is active in migration manager.
Patch by brandonwilliams, reviewed by iamaleksey for CASSANDRA-5236
Merge branch 'cassandra-1.1' into cassandra-1.2
Merge branch 'cassandra-1.2' into trunk
use systemKeyspaceNames instead of hardcoding system + trace
Merge branch 'cassandra-1.2' into trunk
changelog
changelog
Merge branch 'cassandra-1.2' into trunk
Fix SSL client authentication (CASSANDRA-5120)
Merge branch 'cassandra-1.2' into trunk
Fix composite comparator with super columns

patch by slebresne; reviewed by thobbs for CASSANDRA-5287
Merge branch 'cassandra-1.2' into trunk

Conflicts:
	src/java/org/apache/cassandra/config/CFMetaData.java
avoid allocating unused HashMap for RowMutation
Merge branch 'cassandra-1.2' into trunk
special-case single-CF mutations to deserialize to singletonMap instead of HashMap
add single-CF specialization of RowMutation constructor
convert RowMutations on the cql3 path to use more-efficient mutations map
add TODO for builder conversion
convert internal_insert to use more-efficient RowMutation constructor