pip: OpenStack updated requirements of eventlet again
# NOTE: OpenStack avoids the newer versions of eventlet, because of the
# following issue.
# https://github.com/eventlet/eventlet/issues/401
-eventlet!=0.18.3,>=0.18.2,<0.21.0
+eventlet!=0.18.3,>=0.18.2,!=0.20.1,<0.21.0
msgpack-python>=0.3.0 # RPC library, BGP speaker(net_cntl)
netaddr
oslo.config>=1.15.0
