Rigify: fix T70841 - bad bone placement when the metarig object is moved.

Match object orientations during join, as suggested by @pioverfour.

rigify/generate.py

@@ -156,8 +156,13 @@ class Generator(base_generate.BaseGenerator):
         # Select the target rig and join
         select_object(context, obj)
 
+        saved_matrix = obj.matrix_world.copy()
+        obj.matrix_world = metarig.matrix_world
+
         bpy.ops.object.join()
 
+        obj.matrix_world = saved_matrix
+
         # Select the generated rig
         select_object(context, obj, deselect_all=True)