I noticed a some nagios service checks were checking prometheus
alerts which did not exist in our default prometheus configuration.
In one case a prometheus alert did not match the naming convention
of similar alerts.
One nagios service check, ceph_monitor_clock_skew_high, does not
have a corresponding alert at all, so I've changed it to check the
node_ntmp_clock_skew_high
alert, where a node has the label ceph-mon="enabled".
Change-Id: I2ebf9a4954190b8e2caefc8a61270e28bf24d9fa
4fdcff593c