code: func FixUserDataForPerkeepRename() {
  	needsRestart, err := fixUserDataForPerkeepRename()
  	if err != nil {
  		exitf("Could not fix GCE user-data metadata: %v", err)
  	}
  	if needsRestart {
  		if err := resetInstance(); err != nil {
  			exitf("Could not reset instance: %v", err)
  		}
  	}
  }
docs: // FixUserDataForPerkeepRename checks whether the value of "user-data"
  // in the GCE metadata is up to date with the correct systemd service
  // and docker image tarball based on the "perkeep" name. If not
  // (i.e. they're the old "camlistore" based ones), it fixes said
  // metadata. It returns whether the metadata was indeed changed, which
  // indicates that the instance should be restarted for the change to
  // take effect.