Translates 'restore' in french (#416)

tracim/tracim/i18n/fr/LC_MESSAGES/tracim.po

@@ -1564,7 +1564,7 @@ msgstr "Supprimer"
 #: tracim/templates/thread/toolbar.mak:53
 #: tracim/templates/thread/toolbar.mak:57
 msgid "Restore"
-msgstr ""
+msgstr "Restaurer"
 
 #: tracim/templates/folder/forms.mak:12
 msgid "New Folder"