Add the identity to the automatically added fields.
Add the identity to the automatically added fields.

The identity, as set by the first argument to openlog() can be cached
away, and later used as the program name (that's pretty much how
syslogds treat it, too), so add it to the list of automatically
discovered fields.

Signed-off-by: Gergely Nagy <6780fac3b38619ac20422286e4110a70dbba2203@madhouse-project.org>

deirf/libumberlog