[REVIEW] fix for fdo#47285, sorting cells with relative refs may invalidate some

Hey,

[1] fixes a problem when you sort cells with relative refs. The update
for absolute refs needs the information about the original referenced
cell and therefore the relative references should be updated after the
absolute ones. The relative references don't need any information
about their position and therefore there is no problem to update them
after the absolute refs.

Regards,
Markus

[1] http://cgit.freedesktop.org/libreoffice/core/commit/?id=2118ec3630fe12ff2a663c94421780870f264e83