Release the accelerator, and cleanup global references.

Change-Id: Id9931527f1b6d89067bc1e520e521ccfa6e28197
Reviewed-on: https://gerrit.libreoffice.org/16740Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/16751Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>