Don't silence all JJB output when we are installed
Don't silence all JJB output when we are installed

This moves the logging configuration call which disables the majority of
output from JJB to a call path that is only hit when the lint command is
running.

(Previously, just having jenkins-job-linter installed would mean that
all JJB logging output was suppressed.)

OddBloke/jenkins-job-linter