use correct variable for parent pyfan, fixes #3

pyfan.py

@@ -20,7 +20,7 @@ class ThermalZone:
         self.factor = 1 / config["factor"]
         self.name = config["name"]
         self.target = config["target"]
-        self.hwmap = pyfan.hwmap
+        self.hwmap = pyfan_parent.hwmap
         self.pyfan = pyfan_parent
         self.alias_replace = re.compile('|'.join(self.hwmap.keys()))
         self.setup_pwm()