Full search gave me that Twisted wants to know path to initdb and pg_ctl binaries (although it never uses them in case of calendarserver). Problem is they are in /usr/lib/postgresql/9.4/bin and are added to path only for user 'postgres', as it's only have permission to connect to postgresql server in Debian by default trough login. So you need to find how to work around this limitation.
Respectfully, Peteris Krisjanis. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org