pmLookupName - refine error handling with derived metrics
The return status is a little tricky as we make a second attempt for
a derived metric lookup for each unknown name if the original lookup
fails for any metric name, leading to a possible multiplicity of error
statuses ... prefer the status from receive_names(), unless all of the
remaining unknown names are resolved by __dmgetpmid() in which case
success (numpmid) is the right return status.
pmLookupName - refine error handling with derived metrics
The return status is a little tricky as we make a second attempt for
a derived metric lookup for each unknown name if the original lookup
fails for any metric name, leading to a possible multiplicity of error
statuses ... prefer the status from receive_names(), unless all of the
remaining unknown names are resolved by __dmgetpmid() in which case
success (numpmid) is the right return status.