dpkg-maintscript-helper(1): dpkg only has to be unpacked for it to be usable

Some packages use a pre-dependency to ensure a version of dpkg with
dpkg-maintscript-helper is available by the time preinst is run.
Clarify that "available" here means "unpacked", not configured, for
some added peace of mind.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Raphaël Hertzog <hertzog@debian.org>

debian/changelog

@@ -57,6 +57,8 @@ dpkg (1.16.0) UNRELEASED; urgency=low
   [ Jonathan Nieder ]
   * Remove support for use of synchronous sync(2), due to its pernicious
     side-effects and to ease maintenance.
+  * Clarify that an up-to-date dpkg only needs to be unpacked for
+    dpkg-maintscript-helper to work.
 
   [ Updated programs translations ]
   * German (Sven Joachim).

man/dpkg-maintscript-helper.1

@@ -110,7 +110,7 @@ abort\-upgrade/abort\-install, the \fBpostrm\fP renames
 .P
 Given that \fBdpkg\-maintscript\-helper\fP is used in the \fBpreinst\fP,
 using it unconditionally requires a pre-dependency to ensure that the
-required version of dpkg has been configured before. The required version
+required version of dpkg has been unpacked before. The required version
 depends on the command used, for \fBrm_conffile\fP and \fBmv_conffile\fP
 it is 1.15.7.2:
 .P