Push prints error messages correctly

When using docker-app as a plugin, error messages did not appear in the
console.
This is due to the fact that we did never un-mute the docker CLI structure
when Pushing, and that the RunPlugin uses dockerCli.Err() to report
error messages to the user.

This fixes the issue by using the `defer muteDockerCli(cli)()` pattern
that is used everywhere else.

Signed-off-by: Simon Ferquel <simon.ferquel@docker.com>

Author: simonferquel

internal/commands/push.go

@@ -48,7 +48,7 @@ func pushCmd(dockerCli command.Cli) *cobra.Command {
 }
 
 func runPush(dockerCli command.Cli, name string, opts pushOptions) error {
-	muteDockerCli(dockerCli)
+	defer muteDockerCli(dockerCli)()
 	app, err := packager.Extract(name)
 	if err != nil {
 		return err