Do not report missed ldap_gssapi_pricipal as error
If DHCP is built with ldap_gssapi support but ldap_gssapi_principal is not set error level messages is written in the logs. This is totally OK to not have the parameter set.
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1831332 Signed-off-by: Pavel Zhukov pzhukov@redhat.com