Trace when all log entries are deleted
Trace when all log entries are deleted

It can be helpful for debug to know when someone deletes all of the
log entries at once, like when a user clicks the 'Delete all' button
on the web UI. If audit logs are ever implemented, it could be changed
to one of those instead.

Signed-off-by: Matt Spinler <c000c989d08c98662d98f15448f11de169feb92d@us.ibm.com>
Change-Id: I88b5c4a5e7830c64d3283de8f830f0cae4d501da

openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging