fast-export: trivial cleanup

Setting 'commit' to 'commit' is a no-op. It might have been there to
avoid a compiler warning, but if so, it was the compiler to blame, and
it's certainly not there any more.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fast-export.c

@@ -483,7 +483,7 @@ static void get_tags_and_duplicates(struct object_array *pending,
 	for (i = 0; i < pending->nr; i++) {
 		struct object_array_entry *e = pending->objects + i;
 		unsigned char sha1[20];
-		struct commit *commit = commit;
+		struct commit *commit;
 		char *full_name;
 
 		if (dwim_ref(e->name, strlen(e->name), sha1, &full_name) != 1)