m/t/l/cluster: fix wrong metroctl path in launch-cluster wrapper

Change-Id: I3dfd740fb45809bc81555d87083a0476600f60e1
Reviewed-on: https://review.monogon.dev/c/monogon/+/2836
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/test/launch/cluster/metroctl.go b/metropolis/test/launch/cluster/metroctl.go
index fbf968a..e985a64 100644
--- a/metropolis/test/launch/cluster/metroctl.go
+++ b/metropolis/test/launch/cluster/metroctl.go
@@ -15,7 +15,7 @@
 	metroctl "source.monogon.dev/metropolis/cli/metroctl/core"
 )
 
-const metroctlRunfile = "metropolis/cli/metroctl/metroctl_/metroctl"
+const metroctlRunfile = "_main/metropolis/cli/metroctl/metroctl_/metroctl"
 
 // MetroctlRunfilePath returns the absolute path to the metroctl binary available
 // if the built target depends on //metropolis/cli/metroctl. Otherwise, an error