custodia: force reconnect before retrieving CA certs from LDAP
Force reconnect to LDAP as DS might have been restarted after the
connection was opened, rendering the connection invalid.
This fixes a crash in ipa-replica-install with --setup-ca.
https://fedorahosted.org/freeipa/ticket/6207
Reviewed-By: Martin Basti <mbasti@redhat.com>