linux pmda - fix missing initialization for netstat metrics
linux pmda - fix missing initialization for netstat metrics

Found by qa/003 on ia64 grundy.sgi.com SUSE SLES11 SP1.

We must have been simply lucky on other platforms, as this had the
potential to whack data in the linux PMDA's address space, and hence
pmcd (the linux PMDA is a DSO agent by default).

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