Bug 7330 - System preferences editor generates errors in the log with each search

Bug 7330 - System preferences editor generates errors in the log with each search

Adding a check for an empty value in a couple of places
which seem to always get one.

As far as I can tell these places in the script are looping
over ALL the data in the pref files, and sometimes an empty
value comes through. I wonder if this is because of a minor
syntax error in the pref file?

My correction is a stab in the dark since I haven't determined
where the empty value is actually coming from. This change
quiets the errors in the log and doesn't seem to affect
preference search results.

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
No more messages in the logs. Yay!

Ran unit tests on this (t, xt/author, xt, t/db_dependent)- nothing out of the ordinary in any.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>