graph/db: version ForEachSourceNodeChannel

Add a gossip version parameter to ForEachSourceNodeChannel in the Store
interface and both KV/SQL implementations. The VersionedGraph wrapper
delegates with its baked-in version. Convert the
testAddChannelEdgeShellNodes and testForEachSourceNodeChannel tests to
run against both v1 and v2 gossip versions.

graph/db/graph.go

@@ -587,14 +587,6 @@ func (c *ChannelGraph) UpdateEdgePolicy(ctx context.Context,
 	return nil
 }
 
-// ForEachSourceNodeChannel iterates through all channels of the source node.
-func (c *ChannelGraph) ForEachSourceNodeChannel(ctx context.Context,
-	cb func(chanPoint wire.OutPoint, havePolicy bool,
-		otherNode *models.Node) error, reset func()) error {
-
-	return c.db.ForEachSourceNodeChannel(ctx, cb, reset)
-}
-
 // ForEachNodeChannel iterates through all channels of the given node.
 func (c *ChannelGraph) ForEachNodeChannel(ctx context.Context,
 	v lnwire.GossipVersion, nodePub route.Vertex,
@@ -906,6 +898,14 @@ func (c *VersionedGraph) HasChannelEdge(chanID uint64) (bool, bool, error) {
 	return c.db.HasChannelEdge(c.v, chanID)
 }
 
+// ForEachSourceNodeChannel iterates through all channels of the source node.
+func (c *VersionedGraph) ForEachSourceNodeChannel(ctx context.Context,
+	cb func(chanPoint wire.OutPoint, havePolicy bool,
+		otherNode *models.Node) error, reset func()) error {
+
+	return c.db.ForEachSourceNodeChannel(ctx, c.v, cb, reset)
+}
+
 // ForEachNodeChannel iterates through all channels of the given node.
 func (c *VersionedGraph) ForEachNodeChannel(ctx context.Context,
 	nodePub route.Vertex, cb func(*models.ChannelEdgeInfo,