Revert "rc scripts: use common library source"

This reverts commit 56acff7c78.

etc/rc.d/rc.library.source

@@ -126,7 +126,11 @@ extra_addr() {
 
 extra() {
   source <(/usr/bin/fromdos <$EXTRA)
-  [[ "avahi show" =~ $CALLER ]] && extra_name || extra_addr
+  if [[ "avahi show" =~ $CALLER ]]; then
+    extra_name
+  else
+    extra_addr
+  fi
 }
 
 check() {