ipaserver_setup_http: Only use tasks.restore_context for old releases

tasks.restore_context is only used in old releases. The existence of
paths.CACHE_IPA_SESSIONS is used to determine if the call needs to be
done or not.

roles/ipaserver/library/ipaserver_setup_http.py

@@ -183,6 +183,7 @@ def main():
                 subject_base=options.subject_base,
                 auto_redirect=not options.no_ui_redirect,
                 ca_is_configured=options.setup_ca)
+        if hasattr(paths, "CACHE_IPA_SESSIONS"):
             tasks.restore_context(paths.CACHE_IPA_SESSIONS)
 
         ca.set_subject_base_in_config(options.subject_base)