On macOS the sha1 tool is named 'shasum' while on all other unix systems
it is called 'sha1sum'. In order to make all unix provisioning scripts
run on macOS without special case handling a symbolic link is created.
Change-Id: Ib1365cbb0dcb31e68a22959ce939fb450ec7e3f7
Reviewed-by: Joni Jäntti <joni.jantti@qt.io>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>
Reviewed-by: Simo Fält <simo.falt@qt.io>