Do not quote metric names after metrics-core upgrade

patch by yukim; reviewed by jbellis for CASSANDRA-5947
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/metrics/HintedHandoffMetrics.java
	src/java/org/apache/cassandra/metrics/ReadRepairMetrics.java
Merge branch 'cassandra-2.0' into trunk