SelectBox: maxListCount off-by-one bug quick fix

The obsolete height-fitting code has a chance to cause an off-by-one-item bug in the drop down box due to a possible precision loss from [ height -=  height % itemHeight ].

This height fitting code is obsolete and unneeded as of the patch implementing maxListCount where the height is calculated off desired number of items and not prefHeight().  This fix simply removes the old code.

This height fitting is now handled
Merge pull request #456 from SG57/patch-1

SelectBox: maxListCount off-by-one bug quick fix