This change makes the "make docs" command use the correct style. Be aware
that the "global" qdocconfs need to be in the QT_INSTALL_DOCS location
before running "make docs", which effectively means that "make install"
needs to be run in qtbase when doing a prefix build.

Change-Id: Ib4635af0ad45717407a163968d629647898074dc
Reviewed-by: Geir Vattekar <geir.vattekar@nokia.com>