Properly error out on CREATE INDEX on counter tables

patch by slebresne; reviewed by jbellis for CASSANDRA-6160
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/cql3/statements/CreateIndexStatement.java
Handle JMX notification failure for repair

patch by yukim; reviewed by pcmanus for CASSANDRA-6097
Merge branch 'cassandra-1.2' into cassandra-2.0

Conflicts:
	src/java/org/apache/cassandra/tools/NodeProbe.java