Modify the style of translated messages

Translated messages should not be combined with orther literal
strings to create partially translated message.
Although this change is very small, but this is the only one in
the directory VOLUME.

Change-Id: If798aacde9d5d5e8ac2edd49e75099ec255c858e

openstackclient/volume/v2/volume_type.py

@@ -205,8 +205,8 @@ class SetVolumeType(command.Command):
             try:
                 volume_type.set_keys(parsed_args.property)
             except Exception as e:
-                self.app.log.error(_("Failed to set volume type property: ") +
-                                   str(e))
+                self.app.log.error(_("Failed to set volume type"
+                                     " property: %s") % str(e))
                 result += 1
 
         if parsed_args.project: