use dpid_to_str in some places

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
of: StringifyMixin

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
of10: sprinkle StringifyMixin

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
app/quantum_adapter: unbreak quantum change

Now quantum checks attributes strictly on REST request by
the changeset of 61bdda62e8950a9747073e2be7b81cdea0af2f25
Don't send non-standard attribute.

> commit 61bdda62e8950a9747073e2be7b81cdea0af2f25
> Author: Jason Zhang <zhesen@nttmcl.com>
> Date:   Tue Feb 12 18:40:12 2013 -0800
>
>     Raising error if invalid attribute passed in.
>
>     400 will be returned when invalid attributes
>     are passed into Quantum API.
>
>     Fixed the some test cases failed since the
>     enforcement of invalid attribute checking
>
>     Fixes: bug #1076179
>
>     Change-Id: I4e9e2891c444f9dcd051f7b325d3c9403b28db86

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
app/gre_tunnel: pylint

> E: 60,18:PortSet.EventTunnelKeyDel.__init__: Undefined variable 'EventTunnelKeyDel'
> W: 18,0: Unused import logging

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
run_tests: make python interpreter overridable

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>