Deprecate _ builtin translation function
Deprecate _ builtin translation function

This function is discouraged for usage as per oslo.i18n guidelines [1],
so we should deprecate and remove it.

[1] http://docs.openstack.org/developer/oslo.i18n/usage.html

Change-Id: I848ee1dbd16a23c4db42df4690bf139bd769f3e8
Partial-Bug: #1520094

apporc/neutron,klmitch/neutron,cloudbase/neutron,igor-toga/local-snat,klmitch/neutron,huntxu/neutron,huntxu/neutron,bigswitch/neutron,mahak/neutron,noironetworks/neutron,wolverineav/neutron,sebrandon1/neutron,cloudbase/neutron,apporc/neutron,openstack/neutron,mahak/neutron,eayunstack/neutron,bigswitch/neutron,sebrandon1/neutron,noironetworks/neutron,igor-toga/local-snat,mahak/neutron,openstack/neutron,wolverineav/neutron,MaximNevrov/neutron,eayunstack/neutron,openstack/neutron,dims/neutron,dims/neutron,MaximNevrov/neutron