Fixing typo in message format

Fixing a typo in an exception message.
Found during removal of Python 3.5 test in favor of
Python 3.7 in https://review.opendev.org/654641

Change-Id: I23feb09697229de74f6522a0d8cb9ab2a53428ca

ironic_staging_drivers/intel_nm/nm_vendor.py

@@ -200,7 +200,7 @@ class IntelNMVendorPassthru(base.VendorInterface):
             if (kwargs['parameter_name'] not in
                 nm_commands.STATISTICS[kwargs['scope']]):
                     raise exception.InvalidParameterValue(
-                        _('Invalid parameter name %(param)% for scope '
+                        _('Invalid parameter name %(param)s for scope '
                           '%(scope)s') % {'param': kwargs['parameter_name'],
                                           'scope': kwargs['scope']})