Revert "Disable chacha20-poly cipher in sshd config as a workaround."

This reverts commit eff729b.
With new gcc 8.3 chacha20-poly cipher works properly again.

[sshd] Re-enable chacha20-poly cipher. JB#44691

rpm/sshd_config

@@ -22,12 +22,6 @@ HostKey /etc/ssh/ssh_host_ed25519_key
 # Ciphers and keying
 #RekeyLimit default none
 
-# Cipher chacha20-poly1305@openssh.com causes connection error with openssh
-# compiled with gcc 4.9.4: "message authentication code incorrect".
-# This is probably a compiler/openssh bug but as a workaround drop the
-# chacha cipher from supported list for now (see JB#44920).
-Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
-
 # Logging
 #SyslogFacility AUTH
 #LogLevel INFO