src/pmdas/linux/pmda.c: fix typo (metric name) in comment
src/pmdas/linux/pmda.c: fix typo (metric name) in comment

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