As best I can tell, eventlet already does (and always has done) the
right thing, and we were just bad at catching Timeouts.
For some history:
https://github.com/openstack/swift/commit/5db3cb3
https://github.com/openstack/swift/commit/2b3aab8
https://github.com/openstack/swift/commit/da0e013
Change-Id: Iad8109c4a03f006a89e55373cf3ca867d724b3e1
Related-Bug: 1647804