metropolis/cli/metroctl: don't print usage for runtime errors

Change-Id: I91fdca45e874ea1ec9112df556a9a7392fd45bfd
Fixes: https://github.com/monogon-dev/monogon/issues/352
Reviewed-on: https://review.monogon.dev/c/monogon/+/3440
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/cli/metroctl/cmd_takeownership.go b/metropolis/cli/metroctl/cmd_takeownership.go
index 30b9f08..d421f71 100644
--- a/metropolis/cli/metroctl/cmd_takeownership.go
+++ b/metropolis/cli/metroctl/cmd_takeownership.go
@@ -24,7 +24,7 @@
 cluster to issue an owner certificate to for the owner key generated by a
 previous invocation of metroctl install on this machine. A single cluster
 endpoint must be provided with the --endpoints parameter.`,
-	Args: cobra.ExactArgs(0),
+	Args: PrintUsageOnWrongArgs(cobra.ExactArgs(0)),
 	Run:  doTakeOwnership,
 }