Bug 16610 - Regression in SIP2 user password handling

Bug 16610 - Regression in SIP2 user password handling

Previous to bug 14507, SIP2 only did internal authentication. A change
to the way we check empty passwords has caused any empty password to
send back a CQ of Y. Previous to that patch set, a CQ of Y would only be
sent back of the patron password column was NULL. Now, an empty AD field
*always* returns a CQ of Y.

Test Plan:
1) Send a patron information request with an empty AD field
   Note: You must send the AD field or you won't get back a CQ field
2) Note you get back a CQ of Y
3) Apply this patch
4) Repeat step 1
5) Note you now get back a CQ of N

Signed-off-by: Trent Roby <troby@bclib.info>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>