Fix _lookup_serial to compare with proper types.
Fix _lookup_serial to compare with proper types.

Storing a serial number in a long and comparing it to an ogg_uint32_t only
 works if you cast the long down, instead of letting C promote it.


git-svn-id: aaacb87f8b65fb7d6fc622a2ff2a583ecedb130f@17536 0101bb08-14d6-0310-b084-bc0e0c8e3800

soundcloud/tremor,soundcloud/tremor