Build freeVolumeCountMap using dn.Address so the key matches
wdclient.Location.Url during the subsequent lookup. Keying by dn.Id
silently filtered out every replica in deployments where dn.Id is a
short name (e.g. Kubernetes StatefulSet pod name) while the location
Url is a FQDN:port, causing "no healthy replicas" even with ample
free capacity.
Also filter replicas before marking volumes readonly so that a failed
health check no longer strands volumes in readonly state.
Fixes#9145
Chris Lu
73ddb004ab