topology: pep8 fixes
topology: pep8 fixes

Normal pep8 fixes, there were also two instances where I updated a commented
LOG.debug to include exc_info=True so that the traceback will be logged
instead of relying on the error passed in the except.

Signed-off-by: Evan Gray <c2f69a330093c59973f94376329201e16e1fffe7@gmail.com>
Reviewed-by: Iwase Yusuke <bb80e84cc9f5a8f01385872ee89032beb5d4eba7@gmail.com>
Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

TakeshiTseng/ryu,fujita/ryu,fkakuma/ryu,iwaseyusuke/ryu,TakeshiTseng/ryu,fujita/ryu,lagopus/ryu-lagopus-ext,osrg/ryu,osrg/ryu,shinpeimuraoka/ryu,gareging/SDN_Framework,shinpeimuraoka/ryu,osrg/ryu,iwaseyusuke/ryu,iwaseyusuke/ryu,TakeshiTseng/ryu,pichuang/ryu,gareging/SDN_Framework,shinpeimuraoka/ryu,pichuang/ryu,gareging/SDN_Framework,TakeshiTseng/ryu,fkakuma/ryu,pichuang/ryu,fkakuma/ryu,fujita/ryu,iwaseyusuke/ryu,lagopus/ryu-lagopus-ext,gareging/SDN_Framework,iwaseyusuke/ryu,shinpeimuraoka/ryu,shinpeimuraoka/ryu,lagopus/ryu-lagopus-ext,fujita/ryu,gareging/SDN_Framework,TakeshiTseng/ryu,osrg/ryu,fkakuma/ryu,fkakuma/ryu,pichuang/ryu,lagopus/ryu-lagopus-ext,lagopus/ryu-lagopus-ext,osrg/ryu,pichuang/ryu,fujita/ryu