Use format to convert ints to strings

This ensures that on 32bit architectures, where
sometimes an implicit long is created, the resulting
string does not contain a 'L' suffix as generated
by the hex function.

Change-Id: I264f90d68009963fe7a217c2170e1cf2f46ae2bb
Closes-Bug: 1501703

neutron/agent/linux/ip_lib.py

@@ -331,7 +331,7 @@ class IpRuleCommand(IpCommandBase):
                 integers.append(0xffffffff)
 
             # We now have two integers in a list.  Convert to canonical string.
-            return '/'.join(map(hex, integers))
+            return '{0:#x}/{1:#x}'.format(*integers)
 
         def canonicalize(item):
             k, v = item