CopySupport: Do not call manage_afterClone when "duplicate" is true.

manage_afterClone clears workflow history, which is precisely what
"duplicate" is trying to avoid.
This fixes a regression introduced in
  commit 7e810d5a
  Author: Vincent Pelletier <vincent@nexedi.com>
  Date:   Tue Feb 20 17:06:46 2018 +0900

      CopySupport: Factorise clipboard-related methods and code paths.

product/ERP5Type/CopySupport.py

@@ -502,10 +502,11 @@ class CopyContainer:
       new_ob = self._getOb(new_id)
       new_ob._postCopy(self, op=op)
       if is_clone:
-        new_ob.manage_afterClone(new_ob)
+        if duplicate:
+          new_ob._postDuplicate()
+        else:
+          new_ob.manage_afterClone(new_ob)
         new_ob.wl_clearLocks()
-      if duplicate:
-        new_ob._postDuplicate()
       if not set_owner:
         # try to make ownership implicit if possible
         new_ob.manage_changeOwnershipType(explicit=0)