T6013: fix jinja template condition

Author: takehaya

data/templates/ssh/sshd_config.j2

@@ -115,7 +115,7 @@ RekeyLimit {{ rekey.data }}M {{ rekey.time + 'M' if rekey.time is vyos_defined }
 TrustedUserCAKeys /etc/ssh/trusted_user_ca_key
 {% endif %}
 
-{% if trusted_user_ca_key.bind-user is vyos_defined %}
+{% if trusted_user_ca_key is vyos_defined and trusted_user_ca_key.bind_user is vyos_defined %}
 AuthorizedPrincipalsFile /etc/ssh/authorized_principals/%u
 {% elif trusted_user_ca_key is vyos_defined %}
 AuthorizedPrincipalsFile none