Fix dpkg's French usage string for --print-foreign-architectures

It was missing the final “s” and this resulted in a bad bash
auto-completion.

Reported-by: Guillaume Seren <guillaumseren@gmail.com>
Closes: #685863

debian/changelog

@@ -4,6 +4,8 @@ dpkg (1.16.9) UNRELEASED; urgency=low
   * Fix dpkg-source regression in "3.0 (quilt)" source packages while
     unapplying patches that remove all files in a directory. Closes: #683547
   * Fix segfault of “dpkg-query -W -f ''”.
+  * Fix dpkg's French usage string which was missing the final “s“ in
+    --print-foreign-architectures. Closes: #685863
 
   [ Updated programs translations ]
   * Czech (Miroslav Kure).

po/fr.po

@@ -13,7 +13,7 @@ msgstr ""
 "Project-Id-Version: fr\n"
 "Report-Msgid-Bugs-To: debian-dpkg@lists.debian.org\n"
 "POT-Creation-Date: 2012-07-21 02:18+0200\n"
-"PO-Revision-Date: 2012-07-02 12:56+0200\n"
+"PO-Revision-Date: 2012-08-26 15:35+0200\n"
 "Last-Translator: Christian Perrier <bubulle@debian.org>\n"
 "Language-Team: French <debian-l10n-french@lists.debian.org>\n"
 "Language: fr\n"
@@ -3176,7 +3176,7 @@ msgstr ""
 "                                             liste des architectures.\n"
 "  --print-architecture               Afficher l'architecture cible\n"
 "                                             (utilise GCC)\n"
-"  --print-foreign-architecture       Afficher les architectures inconnues\n"
+"  --print-foreign-architectures      Afficher les architectures inconnues\n"
 "                                             autorisées\n"
 "  --compare-versions <a> <rel> <b>   Comparer les numéros de version\n"
 "                                             (voir ci-dessous)\n"