Fix "NameError: name 'cmp' is not defined"

Source: https://codegolf.stackexchange.com/questions/49778/how-can-i-use-cmpa-b-with-python3

Now the wicd daemon starts as "/usr/sbin/wicd -c -f -e -o" wihout
errors, only warnings are left.

wicd-curses also runs but spews warnings into the status line, too.

wicd/networking.py

@@ -644,7 +644,8 @@ class Wireless(Controller):
                 key = 'quality'
             else:
                 key = 'strength'
-            return cmp(x[key], y[key])
+            return ((x[key] > y[key]) - (x[key] < y[key])) # cmp(x[key], y[key])
+
                 
         if not self.wiface:
             return []