Previously, we were setting the environment variable to disable
greendns in eventlet *after* import eventlet. This has no effect, as
eventlet processes environment variables at import time. This patch
moves the setting of EVENTLET_NO_GREENDNS before importing eventlet in
order to correctly disable greendns.
(cherry picked from commit 7c1d964faab33a02fe2366b5194611252be045fc)
(cherry picked from commit 79e6b7fd30a04cdb2374abcaf496b6b5b76084ff)
(cherry picked from commit 4984b3b75b5f7086b7464d9acb940e3fb0334a5e)