spec2ophyd: motors do not appear in *wa* command

[prjemian]

Any instances of EpicsMotor created by the spec2ophyd tool do not appear in the wa (report all known motors). This is a SPEC compatibility command from ophyd. Since it is expected any such motors should appear in the wa command, this is a bug.

[prjemian]

To enable their report in wa, add a labels attribute, such as:

m4 = EpicsMotor('vm7:m4', name='m4', labels=("motor", "fourc"))
m5 = EpicsMotor('vm7:m5', name='m5', labels=("motor",))

[prjemian]

Same for ScalerCH and EpicsSignal