Use _LI instead of _ for info message translation

In patch https://review.openstack.org/#/c/70455 , it was using _
for info message translation but not _LI, this is not correct.

In bp log-messages-translation-domain , we have made some changes
for message translation:
_LI(): info
_LW(): warn
_LE(): exception

This patch was update one info message in base_filter.py use _LI
for message translation.

Change-Id: I2d42c0a9950bf368d7359b9cad61d610b3b41c8f
Merge "Use _LI instead of _ for info message translation"