indexlib: properly differentiate the page_number=None and page_number=0 cases
indexlib: properly differentiate the page_number=None and page_number=0 cases

Signed-off-by: Thomas Petazzoni <a5d87d2bd7c424ee5cbdb4e978635bf653d5a005@enix.org>

dittaeva/ocitysmap,maposmatic/ocitysmap,maposmatic/ocitysmap,maposmatic/ocitysmap,dittaeva/ocitysmap