Bug#315927: apache(-common?): postrm may only use essential stuff on purge

[Lars Wirzenius <liw@iki.fi>]

Package: apache
Version: 1.3.33-6
Severity: important

In the source package the file debian/pkgtemplates/flavours.postrm
contains calls to ucf, but when the package is purged, ucf might not be
on the system anymore. (This may apply to other packages built from the
apache source package. I didn't check.)

>From Policy, 7.2, "Binary Dependencies - Depends, Recommends, Suggests,
Enhances, Pre-Depends": "Note, however, that the postrm cannot rely on
any non-essential packages to be present during the purge phase."

Workaround (for people who run into this): manually keep ucf installed
while purging apache.

Here's what piuparts, my package installation and purging tester,
reports (on the package in sarge):

0min15.5s DEBUG: Starting command: chroot ./tmptA1BgG dpkg --purge
--pending
  (Reading database ... 7587 files and directories currently installed.)
  Removing apache ...
  Purging configuration files for apache ...
  /usr/share/apache/default-configs/apache/access.conf: No such file or
directory
  /usr/share/apache/default-configs/apache/srm.conf: No such file or
directory
  cat: /var/lib/ucf/hashfile: No such file or directory
  cat: /var/lib/ucf/hashfile: No such file or directory
  /var/lib/dpkg/info/apache.postrm: line 31: ucf: command not found
  dpkg: error processing apache (--purge):
   subprocess post-removal script returned error exit status 127
  Errors were encountered while processing:
   apache
0min15.6s ERROR: Command failed (status=256): 'chroot ./tmptA1BgG dpkg
--purge --pending'