klippy: Remove some obscure python2 dependencies

Don't modify dictionaries while iterating them and be careful to use
// when doing an integer divide.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/msgproto.py

@@ -252,7 +252,7 @@ class MessageParser:
     def _parse_buffer(self, value):
         tval = int(value, 16)
         out = []
-        for i in range(len(value)/2):
+        for i in range(len(value) // 2):
             out.append(tval & 0xff)
             tval >>= 8
         out.reverse()