hostname file in etc folder is read only, and not allowing me avoid the qmail error

[Avinash Anand]

"
Installation aborted.

No apport report written because the error message indicates its a followup error from a previous failure.
                          dpkg: error processing qmail (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of qmail-run:
 qmail-run depends on qmail (>= 1.06-2.1); however:
  Package qmail is not configured yet.
dpkg: error processing qmail-run (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 qmail
 qmail-run

"
For such error, I am not able to follow this step

http://askubuntu.com/questions/435786/owncloud-problem-installing-packages

file hostname on my system is read only.
Anyway to replace this hole folder (etc)
KIndly reply

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: qmail 1.06-4
ProcVersionSignature: Ubuntu 3.13.0-92.139~precise1-generic 3.13.11-ckt39
Uname: Linux 3.13.0-92-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.13
Architecture: amd64
Date: Mon Oct 31 00:25:07 2016
InstallationMedia: Ubuntu 12.04.5 LTS "Precise Pangolin" - Release amd64 (20140807.1)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: netqmail
UpgradeStatus: No upgrade log present (probably fresh install)