Changing how commands handles error when it can't connect to IPA server

Creating a method to check if ipa client is configured. Also,
changing scripts to use it instead of duplicating the check.

https://pagure.io/freeipa/issue/6261

Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>

ipaclient/install/ipa_certupdate.py

@@ -34,6 +34,7 @@ from ipaplatform.paths import paths
 from ipaplatform.tasks import tasks
 from ipalib import api, errors, x509
 from ipalib.constants import IPA_CA_NICKNAME, RENEWAL_CA_NAME
+from ipalib.util import check_client_configuration
 
 logger = logging.getLogger(__name__)
 
@@ -50,11 +51,7 @@ class CertUpdate(admintool.AdminTool):
         super(CertUpdate, self).validate_options(needs_root=True)
 
     def run(self):
-        fstore = sysrestore.FileStore(paths.IPA_CLIENT_SYSRESTORE)
-        if (not fstore.has_files() and
-            not os.path.exists(paths.IPA_DEFAULT_CONF)):
-            raise admintool.ScriptError(
-                "IPA client is not configured on this system.")
+        check_client_configuration()
 
         api.bootstrap(context='cli_installer', confdir=paths.ETC_IPA)
         api.finalize()