Reading Tango::DevState attributes does not work
$ TANGO_HOST=aculab-db.esrf.fr:10000 ./mj att read state dev test/rf/rfheartbeat
Attribute State is of unsupported data type:19
$ TANGO_HOST=aculab-db.esrf.fr:10000 ./mj att read state dev test/rf/rfheartbeat
Attribute State is of unsupported data type:19