The user log format string has two special parameters: {{ project_id }}
and {{ lb_id }}. These parameters are documented as being wrapped around
double curly brackets and a whitespace, and are being used as so by
operators/installers. However, the actual substitution is single curly
bracket with no whitespace, i.e. {project_id} and {lb_id}. Fix this
issue by aligning the code with the documentation.
Task: 40444
Story: 2007958
Change-Id: Ifdc24033db288ec615391e576c1c77e6b35aba1f