Full tango name issues

[meguiraun]

If the device contains the fully qualified tango name (eg. tango:b-v-xxxx:10000/sys/tg_test/1) the synoptic fails to find the device class

.....
    classname = db.get_class_for_device(device)
PyTango.DevFailed: DevFailed[
DevError[
    desc = Class not found for tango://b-v-cry-csdb-0:10000/g-a101130/cry/spv-16
  origin = DataBase::db_get_class_for_device()
  reason = DB_IncorrectArguments
severity = ERR]

The device exists and it is accessible.