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

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

Change-Id: I5a8f381b6f8fdb4e8febe9e6a901f7cdc6846646
Merge "Replacement `_` on `_LE` in all LOG.error"