Fix memory leak in tokeniser2.
Fix memory leak in tokeniser2.

svn path=/trunk/hubbub/; revision=4675

prepare/netsurf_libhubbub,servo/libhubbub,prepare/netsurf_libhubbub,adamwight/wmf-parsoid-libhubbub,Achal-Aggarwal/hibbub,prepare/netsurf_libhubbub,adamwight/wmf-parsoid-libhubbub,prepare/netsurf_libhubbub,Achal-Aggarwal/hibbub,Achal-Aggarwal/hibbub,prepare/netsurf_libhubbub,servo/libhubbub,servo/libhubbub,prepare/netsurf_libhubbub,adamwight/wmf-parsoid-libhubbub,adamwight/wmf-parsoid-libhubbub,adamwight/wmf-parsoid-libhubbub,servo/libhubbub,servo/libhubbub,Achal-Aggarwal/hibbub