loopingcall change regresses Trove

[Manoj Kumar]

From what I can tell this commit seems to be causing a regression in Trove:

https://github.com/openstack/oslo.service/commit/ba28d511e08c02803ac834bf563eb30a135c2c6e

The affected Trove code is here:

https://github.com/openstack/trove/blob/master/trove/common/utils.py#L190-L201

The symptoms are that loopingcall ERRORs out.

From looking at the logs, is the backoff not working:

http://logs.openstack.org/30/527230/1/check/legacy-trove-scenario-dsvm-mysql-single/8d14c7d/logs/devstack-gate-post_test_hook.txt.gz#_2017-12-13_15_28_13_520

The 1.28.1 tag for oslo is broken for Trove as a result. We will have to blacklist this version until a fix is available.

[Rico Lin (rico-lin)]

A revert for the previous commit: https://review.openstack.org/#/c/528202

[ChangBo Guo(gcb) (glongwave)]

Just quick approve the revert commit