Fix type error in _customization_sso

Fixes below error:

  File "/usr/share/ovirt-engine/setup/bin/../plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py", line 224, in _customization_sso
    f.write(res)
  TypeError: a bytes-like object is required, not 'str'

Signed-off-by: Martin Perina <mperina@redhat.com>

packaging/setup/plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py

@@ -220,7 +220,7 @@ def _customization_sso(self):
                 prompt=True,
                 default=True,
             )
-            with open(tmpconf, 'wb') as f:
+            with open(tmpconf, 'w') as f:
                 f.write(res)
             self._process_sso_client_registration_result(tmpconf)