We shouldn't assume that xrdp daemon is running under root privilege.
In many cases, root privilege is not really needed for xrdp daemon.
xrdp may fail to load certificate/privkey due to lack of permissions
when running under user privilege. Checking existence of files is not
enough and xrdp should output user-friendly log in such case.
Reported by Debian user in bug 856436 [1].
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=856436
65c1fe87d7