RE: Allow escape in application_name

Dear Horiguchi-san

Thank you for giving comments! I attached new patches.

> > + if (appname == NULL)
> > + appname = "[unknown]";
> > + if (username == NULL || *username
> == '\0')
> > + username = "[unknown]";
> > + if (dbname == NULL || *dbname ==
> '\0')
> > + dbname = "[unknown]";
> >
> > I'm still not sure why these are necessary. Could you clarify that?
>
> It probably comes from my request, just for safety for uncertain
> future. They are actually not needed under the current usage of the
> function, so *I* would not object to removing them if you are strongly
> feel them out of place. In that case, since NULL's leads to SEGV
> outright, we would even not need assertions instead.

Yeah, I followed your suggestion. But we deiced to keep codes clean,
hence I removed the if-statements.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED