check_ping_multiaddr.py

the S array swap was forgotten.
* arcfour.c (arcfour_stream): Likewise.
* arcfour-crypt.c (arcfour_crypt): Likewise.

Rev: src/nettle/ChangeLog:1.233
Rev: src/nettle/arcfour-crypt.c:1.2
Rev: src/nettle/arcfour.c:1.6
Rev: src/nettle/x86/arcfour-crypt.asm:1.5