lib/param: Create a seperate server role for "active directory domain controller"

This will allow us to detect from the smb.conf if this is a Samba4 AD
DC which will allow smarter handling of (for example) accidentially
starting smbd rather than samba.

To cope with upgrades from existing Samba4 installs, 'domain
controller' is a synonym of 'active directory domain controller' and
new parameters 'classic primary domain controller' and 'classic backup
domain controller' are added.

Andrew Bartlett

source4/ldap_server/ldap_server.c

@@ -907,7 +907,7 @@ static void ldapsrv_task_init(struct task_server *task)
 		task_server_terminate(task, "ldap_server: no LDAP server required in member server configuration", 
 				      false);
 		return;
-	case ROLE_DOMAIN_CONTROLLER:
+	case ROLE_ACTIVE_DIRECTORY_DC:
 		/* Yes, we want an LDAP server */
 		break;
 	}