Regression: Index not included when generating help files

When generating qhc / qch files, the help index only contains 1 entry.

Easy to reproduce with the Qt sample:
Qt\4.7.0\examples\help\simpletextviewer\documentation

Recreate the help by using the command line:
qcollectiongenerator.exe simpletextviewer.qhcp -o simpletextviewer.qhc

This creates qhc / qch files without apparent problem.
Now open that documenation (with Qt\4.7.0\examples\help\simpletextviewer\simpletextviewer.pro)
and you can see the problem.