bin/media_client: Fix memory leak

Fix leak of memory allocated to 'app'.
Pointed out by Clang Static Analyzer.

Change-Id: I59d39b76a18893bd284db1d75e40620bb1aee9e2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3480
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
Reviewed-by: Axel Dörfler <axeld@pinc-software.de>

src/bin/media_client/media_client.cpp

@@ -27,8 +27,7 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 
-	BApplication* app = new BApplication(
-		"application/x-vnd.Haiku-media_client");
+	BApplication app("application/x-vnd.Haiku-media_client");
 
 	int ret = 0;
 	if (strcmp(argv[1], "play") == 0) {