Depsgraph: Add missing expansion od custom bone shapes

This was fixed in 2.8 branch but not in master.

source/blender/depsgraph/intern/builder/deg_builder_nodes_rig.cc

@@ -284,6 +284,11 @@ void DepsgraphNodeBuilder::build_rig(Object *object)
 			}
 		}
 
+		/* Custom shape. */
+		if (pchan->custom != NULL) {
+			build_object(NULL, pchan->custom);
+		}
+
 		pchan_index++;
 	}
 }

source/blender/depsgraph/intern/builder/deg_builder_relations_rig.cc

@@ -436,6 +436,11 @@ void DepsgraphRelationBuilder::build_rig(Object *object)
 
 		/* assume that all bones must be done for the pose to be ready (for deformers) */
 		add_relation(bone_done_key, flush_key, "PoseEval Result-Bone Link");
+
+		/* Custom shape. */
+		if (pchan->custom != NULL) {
+			build_object(pchan->custom);
+		}
 	}
 }