Fix pmdalinux handling of long network interface names.
Fix pmdalinux handling of long network interface names.

Interface names like "bond0.127" trip hard-coded constant
buffer offset logic in pmdalinux, which causes incorrect
values (all fields in /proc/net/dev shifted by one) to be
reported for some network.interface metrics.

Reviewed-by: Mark Goodwin <6ab81475d0b27dd61506ecd63b37abed502a6264@redhat.com>

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