Fixed refresh rate calculation for broken drivers.
Fixed refresh rate calculation for broken drivers.

svn path=/trunk/libavg/; revision=5824

hoodie/libavg,yyd01245/libavg,yyd01245/libavg,th3infinity/libavg,scotty007/libavg,hoodie/libavg,libavg/libavg,hoodie/libavg,scotty007/libavg,yyd01245/libavg,hoodie/libavg,yyd01245/libavg,scotty007/libavg,th3infinity/libavg,libavg/libavg,th3infinity/libavg,libavg/libavg,libavg/libavg,scotty007/libavg,th3infinity/libavg