Use Device for Link, fallback to name

If  for the provison network an arbitary name, like overlay is used not default, the Name for the network device was the network name and not the physical device.

overlays/wwinit/etc/systemd/network/10-persistent-net.link.ww

@@ -1,9 +1,16 @@
-# /etc/systemd/network/10-persistent-net.link
+# This file is autogenerated by warewulf 
+# Host:   {{.BuildHost}}
+# Time:   {{.BuildTime}}
+# Source: {{.BuildSource}}
 {{range $devname, $netdev := .NetDevs}}
 {{- if $netdev.Primary}}
 [Match]
 MACAddress={{$netdev.Hwaddr}}
 [Link]
-Name={{$devname}}
-{{- end}}
+{{ if $netdev.Device -}}
+Name={{ $netdev.Device }}
+{{ else -}}
+Name={{ $devname }}
+{{ end -}}
+{{ end -}}
 {{end}}