wait for admin goroutine regardless of -user

If configured, always wait for the control socket to be created before
potentially dropping to a different user.

Another pending patch of mine using pledge(2) to drop privileges and
thus also depends on this sync mechanism, so reduce diff churn.

cmd/yggdrasil/main.go

@@ -282,14 +282,13 @@ func main() {
 		<-done
 	})
 
+	// Wait for other goroutines to finish potentially privileged tasks before dropping privileges.
+	if n.admin != nil {
+		n.admin.Created.Wait()
+	}
+
 	// Change user if requested
 	if *chuserto != "" {
-		// Wait for other goroutines to finish potentially privileged tasks before dropping privileges.
-		if n.admin != nil {
-			// control socket:  UNIX requires filesystem permissions, TCP may use a low privileged port.
-			n.admin.Created.Wait()
-		}
-
 		err = chuser(*chuserto)
 		if err != nil {
 			panic(err)