revert to python binary in test_container.
revert to python binary in test_container.

cython extension was not prefered in normal tests. cause c extension
need re-compile after every changes, while python code do not.

misakwa/thriftpy,keitheis/thriftpy,importcjj/thriftpy,OctavianLee/thriftpy,itnihao/thriftpy,misakwa/thriftpy,keitheis/thriftpy,duydb2/thriftpy,itnihao/thriftpy,misakwa/thriftpy,dan-blanchard/thriftpy,halfcrazy/thriftpy,adsharma/flattools,OctavianLee/thriftpy,dan-blanchard/thriftpy,adsharma/flattools,mariusvniekerk/thriftpy,spladug/thriftpy,OctavianLee/thriftpy,eleme/thriftpy,importcjj/thriftpy,halfcrazy/thriftpy,mariusvniekerk/thriftpy,adsharma/flattools,itnihao/thriftpy,spladug/thriftpy,mariusvniekerk/thriftpy,duydb2/thriftpy,maralla/thriftpy,maralla/thriftpy,duydb2/thriftpy,maralla/thriftpy,eleme/thriftpy