just make a single log entry for all devices with missing DNS

bin/kindnavsync

@@ -195,6 +195,9 @@ def lookup_addresses(kind_devices):
              for name in kind_device.get_alternate_names()}
     lookups = lookup_dns(list(names.keys()))
     LOG.debug("lookups: %r", lookups)
+
+    with_missing_dns = []
+
     for kind_device in sorted(kind_devices.values(), key=attrgetter('name')):
         for name in kind_device.get_alternate_names():
             addrs = lookups.get(name, [])
@@ -203,7 +206,7 @@ def lookup_addresses(kind_devices):
                 break
 
         if not addrs:
-            LOG.error('%s mangler DNS-innslag', kind_device)
+            with_missing_dns.append(kind_device)
             kind_device.ignore_insert = True
         elif len(addrs) > 1:
             LOG.error("%s har flere DNS-innslag, kan ikke velge: %s",
@@ -212,6 +215,10 @@ def lookup_addresses(kind_devices):
         else:
             kind_device.loopback = addrs[0]
 
+    if with_missing_dns:
+        LOG.error("Ignorerer utstyr som mangler DNS-innslag:\n%s",
+                  with_missing_dns)
+
 
 def lookup_dns(names):
     result = defaultdict(list)