checkout: fix memory leak

Discovered via Coverity.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

builtin/checkout.c

@@ -232,6 +232,7 @@ static int checkout_merged(int pos, const struct checkout *state)
 	if (!ce)
 		die(_("make_cache_entry failed for path '%s'"), path);
 	status = checkout_entry(ce, state, NULL);
+	free(ce);
 	return status;
 }