sshd_config: Apply suggested changes

Some of the options have been removed, others are now the default.
MOTD still needs to be printed, the boot environment doesn't include the
pam motd module.

Resolves: rhbz#1872892

share/templates.d/99-generic/config_files/common/sshd_config.anaconda

@@ -1,14 +1,8 @@
-Port 22
 PermitRootLogin yes
-IgnoreRhosts yes
-StrictModes yes
 X11Forwarding yes
 X11DisplayOffset 10
 PrintMotd yes
-XAuthLocation /bin/xauth
-KeepAlive yes
 SyslogFacility AUTHPRIV
-RSAAuthentication yes
 PasswordAuthentication yes
 PermitEmptyPasswords yes
 PermitUserEnvironment yes