Regression from commit 7d9bb549
(Related: #i124638# Second step of DrawingLayer FillAttributes...,
2014-06-02), the problem was that the new
CTF_PM_REPEAT_OFFSET_X..CTF_PM_FILLTRANSNAME range's values overlapped with the
existing CTF_PM_HEADERHEIGHT..CTF_PM_HEADERGRAPHICURL range's values, so
when the new code in XMLPageMasterExportPropMapper::ContextFilter()
tried to tweak header repeat offset properties, it actually disabled
HeaderBackGraphicURL instead.

Change-Id: I9c2700fa71a4ef2a813ec671049ee9d98171b57e