t1403: verify that path exists and is a file

Verify that if the path exists then it is a file using test_path_is_file().

Signed-off-by: Mahendra Dani <danimahendra0904@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1403-show-ref.sh

@@ -196,7 +196,7 @@ test_expect_success 'show-ref --verify with dangling ref' '
 
 	remove_object() {
 		file=$(sha1_file "$*") &&
-		test -e "$file" &&
+		test_path_is_file "$file" &&
 		rm -f "$file"
 	} &&