Bug in user_update script when neither --portal or --quota is specified

[astrochun]

The following error message was encountered when both --portal and --quota were not specified:

Traceback (most recent call last):
  File "scripts/user_update", line 164, in <module>
    if not portal_check or not quota_check:
NameError: name 'portal_check' is not defined

Simple solution is to pre-defined portal_check and quota_check. This avoids the SystemError when either of them do not exists on Grouper

A separate warning should be made to indicate the neither of them are set.