Assorted cleanups for the pdns PMDA 
Assorted cleanups for the pdns PMDA 

From: Nathan Scott <nathans@aconex.com>

Attached patch is some small cleanups:
- split out once-per-fetch logic into separate fetch method
- use single-quoted string where its a literal
- remove some unused variables from original fetch callback



mbaldessari/pcp,andyvand/cygpcpfans,ryandoyle/pcp_original,andyvand/cygpcpfans,adfernandes/pcp,mbaldessari/pcp,mbaldessari/pcp,andyvand/cygpcpfans,mbaldessari/pcp,aeg-aeg/pcpfans,edwardt/pcp,ryandoyle/pcp_original,tjanez/pcp,ryandoyle/pcp_original,adfernandes/pcp,tjanez/pcp,edwardt/pcp,prasincs/pcp,andyvand/cygpcpfans,aeg-aeg/pcpfans,ryandoyle/pcp_original,mbaldessari/pcp,aeg-aeg/pcpfans,tjanez/pcp,adfernandes/pcp,tjanez/pcp,aeg-aeg/pcpfans,wuliming/pcp,prasincs/pcp,andyvand/cygpcpfans,adfernandes/pcp,tjanez/pcp,prasincs/pcp,mbaldessari/pcp,andyvand/cygpcpfans,prasincs/pcp,aeg-aeg/pcpfans,tjanez/pcp,edwardt/pcp,wuliming/pcp,aeg-aeg/pcpfans,wuliming/pcp,adfernandes/pcp,tjanez/pcp,adfernandes/pcp,ryandoyle/pcp_original,tjanez/pcp,ryandoyle/pcp_original,wuliming/pcp,edwardt/pcp,adfernandes/pcp,aeg-aeg/pcpfans,prasincs/pcp,adfernandes/pcp,wuliming/pcp,ryandoyle/pcp_original,edwardt/pcp,edwardt/pcp,edwardt/pcp,wuliming/pcp,andyvand/cygpcpfans,wuliming/pcp,andyvand/cygpcpfans,prasincs/pcp,ryandoyle/pcp_original,aeg-aeg/pcpfans,prasincs/pcp,prasincs/pcp,wuliming/pcp,edwardt/pcp