Comment 12 for bug 1490990

The reason why I adopted --config-dir for multiple directories is that in official docs:

http://docs.openstack.org/developer/oslo.config/cfg.html#loading-config-files

it's said: "The order of configuration files inside the same configuration directory is defined by the alphabetic sorting order of their file names." that made me think it supports multiple dirs, since it refers to 'same' dir.

I am fine with --config-path approach, though I believe we won't see it in L. So there without it, there are two ways to approach:

- reverting all config-dir usages from RDO and RHEL-OSP for Liberty. It's not clear how we maintain backwards compatibility though.
- in RDO/RHEL-OSP, moving config-dir /etc/neutron to the end of arguments list. This breaks the publicly announced ordering guarantee.
- revert neutron change for L and work with oslo.config team on --config-path feature in M, then adopt it in M.

I am not confident whether revert is a viable option, need to talk to @armax.