rev-parse: make "whatchanged -- git-fetch-script" work again.

The latest update to avoid misspelled revs interfered when we
were not interested in parsing non flags or arguments not meant
for rev-list.  This makes these two forms work again:

	git whatchanged -- git-fetch-script

We could enable "!def" in the part this change touches to make
the above work without '--', but then it would cause misspelled
v2.6.14..v2.6.16 to be given to diff-tree and defeats the whole
point of the previous fix.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

rev-parse.c

@@ -294,7 +294,9 @@ int main(int argc, char **argv)
 		}
 		if (verify)
 			die("Needed a single revision");
-		if (lstat(arg, &st) < 0)
+		if ((filter & DO_REVS) &&
+		    (filter & DO_NONFLAGS) && /* !def && */
+		    lstat(arg, &st) < 0)
 			die("'%s': %s", arg, strerror(errno));
 		as_is = 1;
 		show_file(arg);