if relocate is a no-op, don't try to op.
Merge branch 'cassandra-1.2' into cassandra-2.0
Revert "Fix LatencyMetrics returning infinity."

This reverts commit 5e51aa4e6d1d868bb82a1aa2ffaed4613b24ffc1.
getRecentLatency returns zero instead of infinity

Patch by Benedict, reviewed by brandonwilliams for CASSANDRA-6920