Fix broken API test due to change f744ca9bba43bf7696754c28d63dd7184f1e200d

A recent change to Go itself caused breakage in this project because
the API compatibility tester reported a problem. This was caused by
a change in the handling of byte and uint8.

http://code.google.com/p/go/source/detail?r=f744ca9bba43bf7696754c28d63dd7184f1e200d