libdpkg: Remove obsolete internal status aliases

The strings are “postinst-failed” for stat_halfconfigured and
“removal-failed” for stat_halfinstalled.

These were used for backward compatibility during upgrades from ancient
dpkg versions. As they should not appear in newer status files, it's
really safe to remove them now.

debian/changelog

@@ -54,6 +54,8 @@ dpkg (1.15.8) UNRELEASED; urgency=low
     files on package installation. This allows embedded systems to skip
     /usr/share/doc, manpages, etc. Based on work from Tollef Fog Heen and
     Martin Pitt, thanks! Closes: #68788, #68861, #497304, #525567, #583902
+  * Remove obsolete internal status aliases “postinst-failed” for
+    stat_halfconfigured and “removal-failed” for stat_halfinstalled.
 
   [ Updated programs translations ]
   * German (Sven Joachim).

lib/dpkg/parsehelp.c

@@ -109,11 +109,6 @@ const struct namevalue statusinfos[] = {
   NAMEVALUE_DEF("triggers-awaited", stat_triggersawaited),
   NAMEVALUE_DEF("triggers-pending", stat_triggerspending),
   NAMEVALUE_DEF("installed",        stat_installed),
-  /* These are additional entries for reading only, in any order ... */
-  /* XXX: backwards compat., remove. */
-  { .name = "postinst-failed", .value = stat_halfconfigured, .length = 15 },
-  /* XXX: backwards compat., remove. */
-  { .name = "removal-failed",  .value = stat_halfinstalled, .length = 14 },
   { .name = NULL }
 };