[REVIEW-3-6] fix for fdo#55022, crash when opening the test file in ScDBQueryDataIterator

[Markus Mohrhard]

Hey,

[1] fixes a crash when opening the test file. The problem is that we
dereference a past the end element. The code was always wrong but we
fixed another bug in this part of the code for 3-6 so that it now
crashes.

Regards,
Markus

[1] http://cgit.freedesktop.org/libreoffice/core/commit/?id=70412d0f3f7979d3d069be8121d49dbb96775cce