Fix memory corruption when using libtiff v4.0 or newer

One tag was missed when adapting to
libtiff v4.0 uint64 data types.

Upstream libtiff documents the following tags as changed:
   TIFFTAG_FREEBYTECOUNTS
   TIFFTAG_FREEOFFSETS

   TIFFTAG_STRIPBYTECOUNTS
   TIFFTAG_STRIPOFFSETS

   TIFFTAG_TILEBYTECOUNTS
   TIFFTAG_TILEOFFSETS