properly retrieve IP address from array for python2.7
properly retrieve IP address from array for python2.7

for python2.7 IP address(src_ip,dst_ip) conversion doesn't work
as expected and throws

Traceback (most recent call last):
  File "_ctypes/callbacks.c", line 315, in 'calling callback function'
  File "/usr/local/lib/python2.7/site-packages/bcc/table.py", line 526, in raw_cb_
    callback(cpu, data, size)
  File "./examples/networking/tc_perf_event.py", line 60, in print_skb_event
    (cpu, socket.inet_ntop(socket.AF_INET6, src_ip),
ValueError: invalid length of packed IP address string

IP string looks like
[254, 128, 0, 0, 0, 0, 0, 0, 156, 237, 12, 255, 254, 42, 90, 31]

Signed-off-by: Nirmoy Das <6ad020fa725fa73abb9a553bfe35b16e2f80a6a0@suse.de>

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