pmdadm: Fix dmstats metric name
pmdadm: Fix dmstats metric name

Fix names in help in order to match names in pmns.dmstats

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