flags: Inject __class__ attribute to LooseVersion
flags: Inject __class__ attribute to LooseVersion

Currently, ryu-manager uses distutils.version.LooseVersion for
"--zapi-frr-version" to parse the given version sting.
With custom type class for oslo_config.cfg.Opt, oslo_config might access
__class__ attribute for equal comparison.
But in case on Python 2, LooseVersion does not have __class__ attribute
and it causes AttributeError. (This error is not always reproduced)

This patch injects required attribute into LooseVersion and avoids this
problem.

Signed-off-by: IWASE Yusuke <bb80e84cc9f5a8f01385872ee89032beb5d4eba7@gmail.com>
Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

iwaseyusuke/ryu,fujita/ryu,lagopus/ryu-lagopus-ext,fujita/ryu,iwaseyusuke/ryu,osrg/ryu,fujita/ryu,lagopus/ryu-lagopus-ext,osrg/ryu,iwaseyusuke/ryu,osrg/ryu,osrg/ryu,fujita/ryu,iwaseyusuke/ryu,fujita/ryu,lagopus/ryu-lagopus-ext,lagopus/ryu-lagopus-ext,osrg/ryu,iwaseyusuke/ryu,lagopus/ryu-lagopus-ext