Use Property setters

At various places in watcher code, we are using property getters
to set property, in this way the property setters defined are
never used, this patch fixes to use property setters to set
property.

Change-Id: Idb274887f383523cea39277b166ec9b46ebcda85

watcher/decision_engine/strategy/strategies/noisy_neighbor.py

@@ -50,7 +50,7 @@ class NoisyNeighbor(base.NoisyNeighborBaseStrategy):
     @property
     def ceilometer(self):
         if self._ceilometer is None:
-            self._ceilometer = ceil.CeilometerHelper(osc=self.osc)
+            self.ceilometer = ceil.CeilometerHelper(osc=self.osc)
         return self._ceilometer
 
     @ceilometer.setter