[FIX] partner_firstname - error when lastname being empty with demo data, migrated data or imported data

partner_firstname/partner.py

@@ -33,9 +33,10 @@ class ResPartner(Model):
     def _compute_name_custom(self, cursor, uid, ids, fname, arg, context=None):
         res = {}
         for rec in self.read(cursor, uid, ids, ['firstname', 'lastname']):
-            name = '%s %s'%(rec['lastname'] if rec['lastname'] else u"",
-                            rec['firstname'] if rec['firstname'] else u"")
-            res[rec['id']] = name
+            names = [rec['lastname'],
+                     rec['firstname']]
+            fullname = " ".join([s for s in names if s])
+            res[rec['id']] = fullname
         return res
 
     def _write_name(self, cursor, uid, partner_id, field_name, field_value, arg, context=None):