Add two saveas icons for sifr theme.

I create two icons for the sifr-theme (the missing saveas icons).
Hope this is correct. :-)

Change-Id: I9b9063018d6d0662e8805b6cf502262deed46d3c
Reviewed-on: https://gerrit.libreoffice.org/8191Reviewed-by: Joren De Cuyper <jorendc@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>