Remove unused

src/pascooldevices/DiscretePositionsMotor.py

@@ -44,7 +44,6 @@ class Position(object):
         self._description = ""
         self._delta = None
         self._offset = None
-        self._ureg = UnitRegistry()
 
     @property
     def name(self):
@@ -107,8 +106,6 @@ class DiscretePositionsMotor(Device):
 
         super(DiscretePositionsMotor, self).init_device()
 
-        self._ureg = UnitRegistry()
-
         self.motor_device = None
         self.shutter_device = None
         self.protection_mode = NO_PROTECTION