qa/common: use -a option to _get_pids_by_name to find primary pmlogger
qa/common: use -a option to _get_pids_by_name to find primary pmlogger

Looking for 'pmlogger .*-P' which now needs -a option.

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