Update comment

hosting/models.py

@@ -537,7 +537,7 @@ class HostingBillLineItem(AssignPermissionsMixin, models.Model):
     def get_vm_id(self):
         """
         If VM_ID is set in the metadata extract and return it as integer
-        other return -1
+        other return None
 
         :return:
         """
@@ -747,7 +747,7 @@ class FailedInvoice(AssignPermissionsMixin, models.Model):
 
     class Meta:
         permissions = (
-            ('view_failedinvoice', 'View User Card'),
+            ('view_failedinvoice', 'View Failed Invoice'),
         )
 
     @classmethod