checkout: reorder check_filename conditional

If we have a "--" flag, we should not be doing DWIM magic
based on whether arguments can be filenames. Reorder the
conditional to avoid the check_filename() call entirely in
this case. The outcome is the same, but the short-circuit
makes the dependency more clear.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

builtin/checkout.c

@@ -965,7 +965,7 @@ static int parse_branchname_arg(int argc, const char **argv,
 		 */
 		int recover_with_dwim = dwim_new_local_branch_ok;
 
-		if (check_filename(NULL, arg) && !has_dash_dash)
+		if (!has_dash_dash && check_filename(NULL, arg))
 			recover_with_dwim = 0;
 		/*
 		 * Accept "git checkout foo" and "git checkout foo --"