src/pmlogger/rc_pmlogger: important fix after SIGUSR2 for log rolling
src/pmlogger/rc_pmlogger: important fix after SIGUSR2 for log rolling

For systems without systemd, the /etc/init.d/pmlogger script has to
be able to identify pmlogger instances started by pmlogger_check and
pmlogger_daily ... this was not happening correctly after the nightly
log rotation and re-exec of pmlogger.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp