Fix logging_context_format_string input for sahara
Fix logging_context_format_string input for sahara

Change-Id: I960d1fddee8c99c65f13841b37675512dd1ecfd2
Closes-Bug: #1451631

zhangjunli177/sahara,openstack/sahara,esikachev/sahara-backup,egafford/sahara,openstack/sahara,tellesnobrega/sahara,zhangjunli177/sahara,tellesnobrega/sahara,esikachev/sahara-backup,ekasitk/sahara,crobby/sahara,egafford/sahara,ekasitk/sahara,esikachev/sahara-backup,crobby/sahara,zhangjunli177/sahara,crobby/sahara,ekasitk/sahara