Suppress error message if the CRL directory doesn't exist

If the CA fails to deploy then the CRL directory will not exist
but will report an error that it has failed to be removed.
There is no need to try to navigate a directory if it doesn't exist.

Related: https://pagure.io/freeipa/issue/8565

Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>

ipaserver/install/cainstance.py

@@ -231,6 +231,9 @@ def get_crl_files(path=None):
     if path is None:
         path = paths.PKI_CA_PUBLISH_DIR
 
+    if not os.path.exists(path):
+        return
+
     files = os.listdir(path)
     for f in files:
         if f == "MasterCRL.bin":