Bug 19892: Replace numbersphr variable with Koha.Preference('OPACNumbersPreferPhrase...

Bug 19892: Replace numbersphr variable with Koha.Preference('OPACNumbersPreferPhrase') in OPAC

Test Case
1) Check that the following files have been changed properly.
opac/opac-search.pl
 opac/opac-main.pl
 koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-advsearch.tt

2)Apply bug
3) Check that there are no differences in behaviour as a result of the patch.

Signed-off-by: Roch D'Amour <roch.damour@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>