Remove libtomcrypt

Tomcrypt in corosync is for long time not updated. Because we have
support for libnss, libtomcrypt can be removed.

Also few leftovers (AES is 256 bits, not 128, ...) are removed.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Steven Dake <sdake@redhat.com>