[FIX] project: don't copy remaining hours when duplicating tasks

Since we're not duplicating work items when duplicating tasks during
project duplication, it doesn't make sense to duplicate the
likely correspondingly adjusted remaining hour.

Behave as if the planned hours had just been set/reset and set the
remaining hours of the new task to that instead.

fixes #8985

addons/project/project.py

@@ -698,9 +698,12 @@ class task(osv.osv):
     def copy_data(self, cr, uid, id, default=None, context=None):
         if default is None:
             default = {}
+        current = self.browse(cr, uid, id, context=context)
         if not default.get('name'):
-            current = self.browse(cr, uid, id, context=context)
             default['name'] = _("%s (copy)") % current.name
+        if 'remaining_hours' not in default:
+            default['remaining_hours'] = current.planned_hours
+
         return super(task, self).copy_data(cr, uid, id, default, context)
 
     def _is_template(self, cr, uid, ids, field_name, arg, context=None):