Bug 29054: Add verbose check for warn in advance_notices.pl

Bug 29054: Add verbose check for warn in advance_notices.pl

To test:
1) Set EnhancedMessagingPreferences to Don't allow
2) In the koha-shell, run misc/cronjobs/advance_notices.pl -c
3) Note that you see the warning "The "EnhancedMessagingPreferences"
syspref is off... etc."
4) Apply the patch and restart services
5) In the koha-shell, run misc/cronjobs/advance_notices.pl -c and note
the warning no longer shows
6) Still in the shell, run misc/cronjobs/advance_notices.pl -c -v and
note the warning does show

Sponsored-by: Catalyst IT
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>