Don't depend on cassandra config for nodetool ring

Backport of CASSANDRA-7508 to cassandra-2.0 by Tyler Hobbs
Merge branch 'cassandra-2.0' into cassandra-2.1.0

Conflicts:
	CHANGES.txt
	src/java/org/apache/cassandra/tools/NodeCmd.java
Merge branch 'cassandra-2.1.0' into cassandra-2.1