Bug#996418: dbus-update-activation-environment: sets wrong PATH since March 2021

[Matt Burt]

See also #984782 which I believe is a duplicate of this one. I'd 
suggested a solution pretty much the same as Mirabilos's patch above. I 
can't see any reason why the PAM file packaged with xrdp shouldn't use 
pam_env.so on Debian (and hence Ubuntu).

Thanks.
--
Matt