Replacement `_` on `_LE` in all LOG.exception

oslo.i18n uses different marker functions to separate the
translatable messages into different catalogs, which the translation
teams can prioritize translating.  For details, please refer to:
http://docs.openstack.org/developer/oslo.i18n/guidelines.html#guidelines-for-use-in-openstack

There were not marker fuctions some places in directory network.
This commit makes changes:
* Add missing marker functions
* Use ',' instead of '%' while adding variables to log messages

Added a hacking rule for the log exception about checking
translation for it.

Change-Id: If80ea6f177bb65afcdffce71550bb38fedcc54eb
Merge "Replacement `_` on `_LE` in all LOG.exception"