ARC4 Removed From OpenSSL

The FIPS 140-2 Approved Algorithms for OpenSSH section requires updates to reflect that the ARC4 algorithm has been removed from OpenSSH.

As a result, remove the following content from this section:

Attempts to use non-approved algorithms fail, as shown in this example:

jdoc:~$ ssh -c arcfour somehost
Unknown cipher type 'arcfour'