bug 4508: fix crash when editing patron attributes or message prefs

bug 4508: fix crash when editing patron attributes or message prefs

When editing patron attributes or messaging preferences on the
patron editor, Koha would crash with the following error:

Software error:
Can't use an undefined value as an ARRAY reference at
/home/koha/kohaclone/C4/SQLHelper.pm line 186.

This would occur only when editing the specific attribute
or message preferences section, not when editing the entire
patron record.

Signed-off-by: Galen Charlton <gmcharlt@gmail.com>