Revert "Proxy: Construct pchan hash when syncing armature proxy"

This reverts commit 9b5a32cbfb.

Apparently it is possible to have other thread mocking around with the hash.

Needs deeper investigation, for the time being reverting to prevent crashes.

source/blender/blenkernel/intern/armature.c

@@ -1781,7 +1781,6 @@ static void pose_proxy_synchronize(Object *ob, Object *from, int layer_protected
 	BLI_duplicatelist(&pose->agroups, &frompose->agroups);
 	pose->active_group = frompose->active_group;
 
-	BKE_pose_channels_hash_make(frompose);
 	for (pchan = pose->chanbase.first; pchan; pchan = pchan->next) {
 		pchanp = BKE_pose_channel_find_name(frompose, pchan->name);