Clean up more pylint warnings in pmdastap_json.python.
Clean up more pylint warnings in pmdastap_json.python.

prasincs/pcp,tjanez/pcp,aeg-aeg/pcpfans,edwardt/pcp,prasincs/pcp,edwardt/pcp,tjanez/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,wuliming/pcp,aeg-aeg/pcpfans,wuliming/pcp,adfernandes/pcp,edwardt/pcp,edwardt/pcp,prasincs/pcp,prasincs/pcp,edwardt/pcp,tjanez/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,aeg-aeg/pcpfans,tjanez/pcp,edwardt/pcp,wuliming/pcp,adfernandes/pcp,wuliming/pcp,tjanez/pcp,edwardt/pcp,adfernandes/pcp,edwardt/pcp,tjanez/pcp,wuliming/pcp,adfernandes/pcp,tjanez/pcp,wuliming/pcp,prasincs/pcp,adfernandes/pcp,prasincs/pcp,prasincs/pcp,prasincs/pcp,aeg-aeg/pcpfans,tjanez/pcp,aeg-aeg/pcpfans,wuliming/pcp,wuliming/pcp,aeg-aeg/pcpfans