Hi,
It seems that there is a wrong path in the package pg_filedump :
$ dpkg -s postgresql-filedump|grep Version
Version: 9.5.0-1.pgdg80+1
$ dpkg -L postgresql-filedump
/.
/usr
/usr/share
/usr/share/doc
/usr/share/doc/postgresql-filedump
/usr/share/doc/postgresql-filedump/changelog.Debian.gz
/usr/share/doc/postgresql-filedump/copyright
/usr/share/doc/postgresql-filedump/README.pg_filedump
/usr/lib
/usr/lib/postgresql
/usr/lib/postgresql/9.4
/usr/lib/postgresql/9.4/bin
/usr/lib/postgresql/9.4/bin/pg_filedump
The path contains 9.4, not 9.5, obviously a mistake,
Regards,
--
Sébastien