Doc for ph_hamming_distance is wrong

[rfalke]

It currently reads

/* ! /brief dct video robust hash
 *   Compute video hash based on the dct of normalized video 32x32x64 cube
 *   /param file name of file
 *   /param hash ulong64 value for hash value
 *   /return int value - less than 0 for error
 */
int ph_hamming_distance(const ulong64 hash1,const ulong64 hash2);