Make POW check log less verbose.

1 job for master in 3 minutes and 21 seconds
Status Job ID Name Coverage
  Test
failed #168877463
piri-snapshot

00:03:21

 
Name Stage Failure
failed
piri-snapshot Test
[ERROR] Please refer to dump files (if any exist) [date]-jvmRun[N].dump, [date].dumpstream and [date]-jvmRun[N].dumpstream.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
ERROR: Job failed: exit code 1