Updated openstack/openstack
Project: openstack/oslo.concurrency  19f07c600c1c5f142c06b8261360e230b97b2c69

Add a TODO for retrying pull request #20

Sometime in a future retrying version there will
likely/hopefully exist a ability to more easily
filter on specific exceptions; this commit adds a
note to the upstream pull request that may add this
feature.

Change-Id: I44f1c9fe4fbbd5f77032ca7bfff4e2e6b7ff7622