bcache: Kill op->replace

This is prep work for converting bch_btree_insert to
bch_btree_map_leaf_nodes() - we have to convert all its arguments to
actual arguments. Bunch of churn, but should be straightforward.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/request.h

@@ -33,6 +33,7 @@ struct search {
 	unsigned		flush_journal:1;
 
 	unsigned		insert_data_done:1;
+	unsigned		replace:1;
 
 	uint16_t		write_prio;
 
@@ -44,6 +45,7 @@ struct search {
 
 	/* Anything past this point won't get zeroed in search_alloc() */
 	struct keylist		insert_keys;
+	BKEY_PADDED(replace_key);
 };
 
 unsigned bch_get_congested(struct cache_set *);