ldapupdate: Add support for Debian multiarch

And since Fedora 28 dropped support for non-64bit, hardcode default LIBARCH as 64.

Fixes: https://pagure.io/freeipa/issue/7555
Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>
Reviewed-By: Christian Heimes <cheimes@redhat.com>

ipaplatform/base/paths.py

@@ -385,6 +385,7 @@ class BasePathNamespace(object):
     GETENT = '/usr/bin/getent'
     SSHD = '/usr/sbin/sshd'
     SSSCTL = '/usr/sbin/sssctl'
+    LIBARCH = "64"
 
 
 paths = BasePathNamespace()