[FIX] maintenance: compute method failed to assign error

before this commit, on opening equipment form view a
traceback is shown saying ompute method failed to assign
error for field display_name

this is related to: https://github.com/odoo/odoo/commit/3c62ca1eb96d571b2b686b5caee370324c589ab4

after this commit, no traceback wont be shown to user

closes odoo/odoo#129978

Signed-off-by: Tiffany Chang <tic@odoo.com>

addons/maintenance/models/maintenance.py

@@ -95,9 +95,9 @@ class MaintenanceEquipment(models.Model):
     @api.depends('serial_no')
     def _compute_display_name(self):
         for record in self:
-            if record.name and record.serial_no:
+            if record.serial_no:
                 record.display_name = record.name + '/' + record.serial_no
-            if record.name and not record.serial_no:
+            else:
                 record.display_name = record.name
 
     @api.model