HPCC-17471 LDAP DN not copied to cached user

When an admin logs in, his LDAP Distinguished Name is queried and saved in
his ISecUser structure. However, when that object is cached, the DN field
is not copied. This PR ensure that field persists when a user object is copied.

Signed-off-by: Russ Whitehead <william.whitehead@lexisnexis.com>

system/security/LdapSecurity/ldapsecurity.cpp

@@ -227,6 +227,7 @@ void CLdapSecUser::copyTo(ISecUser& destination)
     dest->setUserSid(m_usersid.length(), m_usersid.toByteArray());
     dest->setUserID(m_userid);
     dest->setPasswordExpiration(m_passwordExpiration);
+    dest->setDistinguishedName(m_distinguishedName);
 }
 
 ISecUser * CLdapSecUser::clone()