recent discussions on the ML have led to the decision to eliminate all
translations for messages that are destined for log files but retain
them for messages that are going to be returned as exceptions and
potentially shown to end users via an API. see [1], [2].
This change does that as follows.
1. If a string is being used to generate an exception, it will still be translated.
Still kuryr_libnetwork used _LE, _LW, _LI for these translations
2. If a string is used for a logging message, remove the use of _LE, _LW, _LI.
[1] http://lists.openstack.org/pipermail/openstack-operators/2017-March/012887.html
[2] http://lists.openstack.org/pipermail/openstack-dev/2017-March/113365.html
Change-Id: Ic2efcea9a1e2e785a8678c86a0b1209d68bb2a1c
793a6e52b1