Correct plural form translation for table caption

See f51fa04#commitcomment-9330335

Thanks to @jerzyk for reporting

src/oscar/apps/dashboard/catalogue/tables.py

@@ -1,5 +1,5 @@
 from django.utils.safestring import mark_safe
-from django.utils.translation import ugettext_lazy as _, ugettext_noop
+from django.utils.translation import ugettext_lazy as _, ungettext_lazy
 
 from django_tables2 import Column, LinkColumn, TemplateColumn, A
 
@@ -64,8 +64,7 @@ class CategoryTable(DashboardTable):
         orderable=False)
 
     icon = "sitemap"
-    caption_singular = ugettext_noop("{count} Category")
-    caption_plural = ugettext_noop("{count} Categories")
+    caption = ungettext_lazy("%s Category",  "%s Categories")
 
     class Meta(DashboardTable.Meta):
         model = Category

src/oscar/apps/dashboard/tables.py

@@ -1,22 +1,21 @@
-from django.utils.translation import ungettext, ugettext_noop
+from django.utils.translation import ungettext_lazy
 
 from django_tables2 import Table
 
 
 class DashboardTable(Table):
     _caption = None
-    caption_singular = ugettext_noop('{count} Row')
-    caption_plural = ugettext_noop('{count} Rows')
+    caption = ungettext_lazy('{count} Row', '{count} Rows')
 
     @property
     def caption(self):
-        if self._caption:
+        # Allow overriding the caption with an arbitrary string that we cannot
+        # interpolate the number of rows in
+        try:
+            return self._caption % self.paginator.count
+        except TypeError:
             return self._caption
 
-        return (ungettext(self.caption_singular, self.caption_plural,
-                          self.paginator.count)
-                .format(count=self.paginator.count))
-
     @caption.setter
     def caption(self, caption):
         self._caption = caption