Removed unused solar.h reference in sot

Change-Id: If49a8b583c8805e31abe158c31b3d2c9c79e6e27
Reviewed-on: https://gerrit.libreoffice.org/7518
Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>