package postgresql-contrib-9.6 9.6.2-1 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 2

[JCenteno]

removing Postgresql packages from system and the error appeared.

ProblemType: Package
DistroRelease: Ubuntu 17.04
Package: postgresql-contrib-9.6 9.6.2-1
ProcVersionSignature: Ubuntu 4.10.0-19.21-generic 4.10.8
Uname: Linux 4.10.0-19-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
Date: Sun May 28 14:13:02 2017
DpkgTerminalLog:
 Removing postgresql-contrib-9.6 (9.6.2-1) ...
 update-alternatives: error: alternative path /usr/share/postgresql/9.6/man/man1/postmaster.1.gz doesn't exist
 dpkg: error processing package postgresql-contrib-9.6 (--remove):
  subprocess installed pre-removal script returned error exit status 2
DuplicateSignature:
 package:postgresql-contrib-9.6:9.6.2-1
 Removing postgresql-contrib-9.6 (9.6.2-1) ...
 update-alternatives: error: alternative path /usr/share/postgresql/9.6/man/man1/postmaster.1.gz doesn't exist
 dpkg: error processing package postgresql-contrib-9.6 (--remove):
  subprocess installed pre-removal script returned error exit status 2
ErrorMessage: subprocess installed pre-removal script returned error exit status 2
InstallationDate: Installed on 2017-05-26 (1 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
RelatedPackageVersions:
 dpkg 1.18.10ubuntu2
 apt 1.4
SourcePackage: postgresql-9.6
Title: package postgresql-contrib-9.6 9.6.2-1 failed to install/upgrade: subprocess installed pre-removal script returned error exit status 2
UpgradeStatus: No upgrade log present (probably fresh install)

[dino99 (9d9)]

That version is now dead
http://news.softpedia.com/news/ubuntu-17-04-zesty-zapus-has-reached-end-of-life-upgrade-to-ubuntu-17-10-now-519360.shtml