HPCC-11717 LDAP login for system Admin fails on non-ActiveDirectory

Do not try to query DN and other unnecessary LDAP information about an
authenticated non-ActiveDirectory LDAP system admin. Continue querying
this information if it is an HPCC system admin and if its an HPCC user
account (ou=users,ou=ecl).

Signed-off-by: William Whitehead <william.whitehead@lexisnexis.com>