fix issue with unpacking sample counts (#1630)

When unpacking sample counts as "individual" counts (no longer
monotonic), it writes the total sample count to a value 1 past the
individual sample counts, but this is not in the packed data, so do not
expect to unpack that many values. The buffer just needs to be allocated
one value larger to avoid write past end of buffer which is taken care
of in the update_pack_unpack_ptrs function

Signed-off-by: Kimball Thurston <kdt3rd@gmail.com>

src/lib/OpenEXRCore/decoding.c

@@ -292,8 +292,6 @@ default_decompress_chunk (exr_decode_pipeline_t* decode)
             (((uint64_t) decode->chunk.width) *
              ((uint64_t) decode->chunk.height));
 
-        if ((decode->decode_flags & EXR_DECODE_SAMPLE_COUNTS_AS_INDIVIDUAL))
-            sampsize += 1;
         sampsize *= sizeof (int32_t);
 
         rv = decompress_data (