[FIX] account_asset: don't recompute depreciation board on state change

When a user goes through the trouble of manually modifying the
depreciation lines he will lose all his work when clicking on 'reset to
draft'. Furthermore, if he then goes through the trouble of repairing
the problem by once again manually changing the depreciation lines he
will again lose his work when pressing confirm.

opw-678678

addons/account_asset/account_asset.py

@@ -358,7 +358,7 @@ class AccountAssetAsset(models.Model):
     @api.multi
     def write(self, vals):
         res = super(AccountAssetAsset, self).write(vals)
-        if 'depreciation_line_ids' not in vals:
+        if 'depreciation_line_ids' not in vals and 'state' not in vals:
             self.compute_depreciation_board()
         return res