patch-ids: replace the seen indicator with a commit pointer

The cherry_pick_list was looping through the original side checking the
seen indicator and setting the cherry_flag on the commit.  If we save
off the commit in the patch_id we can set the cherry_flag on the correct
commit when running through the other side when a patch_id match is found.

Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/patch-ids.h b/patch-ids.h
index 9569ee0..dea1ecd 100644
--- a/patch-ids.h
+++ b/patch-ids.h
@@ -4,7 +4,7 @@
 struct patch_id {
 	struct hashmap_entry ent;
 	unsigned char patch_id[GIT_SHA1_RAWSZ];
-	char seen;
+	struct commit *commit;
 };
 
 struct patch_ids {