db: match placeholders with columns

Soju inserts 9 columns but only with 8 placeholders. This causes
channels not being saved properly and also logging errors like this:

    downstream ...: failed to create or update channel ...: 8 values for 9 columns

db.go

@@ -596,7 +596,7 @@ func (db *DB) StoreChannel(networkID int64, ch *Channel) error {
 	} else {
 		var res sql.Result
 		res, err = db.db.Exec(`INSERT INTO Channel(network, name, key, detached, detached_internal_msgid, relay_detached, reattach_on, detach_after, detach_on)
-			VALUES (?, ?, ?, ?, ?, ?, ?, ?)`,
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`,
 			networkID, ch.Name, key, ch.Detached, toNullString(ch.DetachedInternalMsgID), ch.RelayDetached, ch.ReattachOn, detachAfter, ch.DetachOn)
 		if err != nil {
 			return err