import "input" from "builtins" for python v2/v3 compatibility

Signed-off-by: Yonghong Song <yhs@plumgrid.com>

examples/distributed_bridge/main.py

@@ -3,6 +3,7 @@
 # Licensed under the Apache License, Version 2.0 (the "License")
 
 from sys import argv
+from builtins import input
 from pyroute2 import IPRoute, NetNS, IPDB, NSPopen
 from simulation import Simulation
 from subprocess import PIPE