* cipher/cipher-ocb.c (double_block): Change to input/output
host-endian block instead of big-endian buffer.
(double_block_cpy): Remove.
(bit_copy): Use fixed length copy and 'u64' for calculations.
(ocb_get_L_big): Handle block endian conversions for double_block.
(_gcry_cipher_ocb_setkey): Handle block endian conversions for
double_block.
(_gcry_cipher_ocb_set_nonce): Set full length of 'ktop' to zero; Drop
length parameter for bit_copy.