Remove units for humidity in Wundeground sensor (#3018)

* Remove units for humidity

Wunderground returns the information with the units.

* Trim the % from the return value of humidity

homeassistant/components/sensor/wunderground.py

@@ -101,7 +101,10 @@ class WUndergroundSensor(Entity):
     def state(self):
         """Return the state of the sensor."""
         if self.rest.data and self._condition in self.rest.data:
-            return self.rest.data[self._condition]
+            if self._condition == 'relative_humidity':
+                return int(self.rest.data[self._condition][:-1])
+            else:
+                return self.rest.data[self._condition]
         else:
             return STATE_UNKNOWN