netwatch-dns: check with eworm.de and eworm.net

This should prevent against DENIC outages...

https://blog.denic.de/en/denic-reports-resolved-dnssec-disruption-affecting-de-domains/

global-functions.rsc

@@ -816,11 +816,12 @@
     :retry {
       :set I ($I ^ 1);
       :resolve ("low-ttl.eworm." . ({ "de"; "net" }->$I));
-      :return true;
     } delay=50ms max=6;
-  } on-error={ }
+  } on-error={
+    :return false;
+  }
 
-  :return false;
+  :return true;
 }
 
 # check if system is is fully connected (default route reachable, DNS resolving, time sync)