Don't show pageX as nam of the page

in case pageX is used for saving remove that on loading. This name is used
on saving if e.g. no name for the page was set. This fixes the problem that
after save/load of a document all slides/pages are named pageX.



Reviewed by: boemann
(cherry picked from commit 4deb1cab33459e7353abb68ccb01dd0b56f4754c)