graph/db: version highest chan id

Add a gossip version parameter to HighestChanID in the Store interface
and both KV/SQL implementations. Update callers in the discovery
ChanSeries and server bootstrap code.

graph/db/graph.go

@@ -688,8 +688,10 @@ func (c *ChannelGraph) AddEdgeProof(chanID lnwire.ShortChannelID,
 }
 
 // HighestChanID returns the "highest" known channel ID in the channel graph.
-func (c *ChannelGraph) HighestChanID(ctx context.Context) (uint64, error) {
-	return c.db.HighestChanID(ctx)
+func (c *ChannelGraph) HighestChanID(ctx context.Context,
+	v lnwire.GossipVersion) (uint64, error) {
+
+	return c.db.HighestChanID(ctx, v)
 }
 
 // ChanUpdatesInHorizon returns all known channel edges with updates in the
@@ -950,6 +952,11 @@ func (c *VersionedGraph) DisabledChannelIDs() ([]uint64, error) {
 	return c.db.DisabledChannelIDs(c.v)
 }
 
+// HighestChanID returns the "highest" known channel ID in the channel graph.
+func (c *VersionedGraph) HighestChanID(ctx context.Context) (uint64, error) {
+	return c.db.HighestChanID(ctx, c.v)
+}
+
 // ChannelID attempts to lookup the 8-byte compact channel ID.
 func (c *VersionedGraph) ChannelID(chanPoint *wire.OutPoint) (uint64, error) {
 	return c.db.ChannelID(c.v, chanPoint)