qa/964: take better control of pmlogger(s) from pmmgr
qa/964: take better control of pmlogger(s) from pmmgr

Any pmlogger process under pmmgr's control will mess up the pmlogger
counting in this test.

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