When a number format for a cell (for example percent) is applied
it is highlighted in the toolbar but not the equal button in the
sidebar. This patch fixes this issue.

Change-Id: I958b1fd152bc2b756a6320b7cb4ebb15ac601f2c
Reviewed-on: https://gerrit.libreoffice.org/18283Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>