hashmap_get{,_from_hash} return "struct hashmap_entry *"

Update callers to use hashmap_get_entry, hashmap_get_entry_from_hash
or container_of as appropriate.

This is another step towards eliminating the requirement of
hashmap_entry being the first field in a struct.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -5217,8 +5217,11 @@ int todo_list_rearrange_squash(struct todo_list *todo_list)
 					break;
 			}
 
-			if ((entry = hashmap_get_from_hash(&subject2item,
-							   strhash(p), p)))
+			entry = hashmap_get_entry_from_hash(&subject2item,
+						strhash(p), p,
+						struct subject2item_entry,
+						entry);
+			if (entry)
 				/* found by title */
 				i2 = entry->i;
 			else if (!strchr(p, ' ') &&