podman-mac-helper: install: do not error if already installed

Since commit bae07b6ea2 we exit with 1 one errors. This caused problem
for the mac installer which fails because of the error now.
If the helper is already installed do not treat this as hard error and
just log it instead.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

cmd/podman-mac-helper/install.go

@@ -93,7 +93,8 @@ func install(cmd *cobra.Command, args []string) error {
 	fileName := filepath.Join("/Library", "LaunchDaemons", labelName)
 
 	if _, err := os.Stat(fileName); err == nil || !os.IsNotExist(err) {
-		return errors.New("helper is already installed, uninstall first")
+		fmt.Fprintln(os.Stderr, "helper is already installed, skipping the install, uninstall first if you want to reinstall")
+		return nil
 	}
 
 	prog, err := installExecutable(userName)