Fix ping probe command. (#538)
Fix ping probe command. (#538)

= Add a LogMetrics function to options that doesn't do anything.
= Add a command line flag to specify IP version.

Fixes: https://github.com/google/cloudprober/issues/532
PiperOrigin-RevId: 348549443
google/cloudprober,cloudprober/cloudprober,google/cloudprober,cloudprober/cloudprober,cloudprober/cloudprober