test: update integration tests

- remove get_supported() at test_request_reply_v12.py.
  use 'is_supported()' if any test wants to skip.
- print results summary.

Signed-off-by: HIYAMA Manabu <hiyama.manabu@po.ntts.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
packet lib: fix a bug in ipv6

ERROR: Failure: AttributeError ('module' object has no attribute 'IPPROTO_ICMP6')
----------------------------------------------------------------------
Traceback (most recent call last):
(...)
  File "/home/openflow/git/osrg/ryu/ryu/lib/packet/ipv6.py", line 68, in <module>
    ipv6.register_packet_type(icmp6.icmp6, inet.IPPROTO_ICMP6)
AttributeError: 'module' object has no attribute 'IPPROTO_ICMP6'

Signed-off-by: HIYAMA Manabu <hiyama.manabu@po.ntts.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>