fix upgrade: wait for proper DS socket after DS restart

DS restart executed by upgrade plugin causes that upgrade framework
is waiting for the improper socket. It leads to TimeoutError because
DS is not listening on 389 port during upgrade. This commit fixes the issue.

Required for: https://fedorahosted.org/freeipa/ticket/5665

Reviewed-By: Tomas Babej <tbabej@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>

ipaserver/install/ldapupdate.py

@@ -43,7 +43,6 @@ from ipaplatform.paths import paths
 from ipaplatform import services
 from ipapython.dn import DN
 from ipapython.ipa_log_manager import log_mgr
-from ipapython.ipautil import wait_for_open_socket
 
 if six.PY3:
     unicode = str
@@ -945,5 +944,4 @@ class LDAPUpdate:
     def restart_ds(self):
         dirsrv = services.knownservices.dirsrv
         self.log.debug('Restarting directory server to apply updates')
-        dirsrv.restart()
-        wait_for_open_socket(self.socket_name)
+        dirsrv.restart(ldapi=self.ldapi)