Pull in patched eventlet to fix Second Simultaneous errors

We have patched eventlet to resolve the issues around
Second simultanous read errors. Pulling in the eventlet
pull request here.

This is a temporary workaround until the changes get merged
into eventlet and released at which point this will be dropped.

Closes-bug: #1308079
Closed-bug: #1229475
Closed-bug: #1308045
Change-Id: I0495f8c443429d9bdbbd97d46fe9a8e180b867ee
Merge "Pull in patched eventlet to fix Second Simultaneous errors"