Fix a copy-and-paste issue found by coverity

Fixes CID 980650; bugfix on 0.2.4.10-alpha.

changes/cov980650

+  o Minor bugfixes:
+    - Fix a copy-and-paste error when adding a missing A1 to a routerset
+      because of GeoIPExcludeUnknown. Fix for coverity CID 980650.
+      Bugfix on 0.2.4.10-alpha.

src/or/routerset.c

@@ -255,7 +255,7 @@ routerset_add_unknown_ccs(routerset_t **setp, int only_if_some_cc_set)
   }
   if (add_a1) {
     smartlist_add(set->country_names, tor_strdup("a1"));
-    smartlist_add(set->country_names, tor_strdup("{a1}"));
+    smartlist_add(set->list, tor_strdup("{a1}"));
   }
 
   if (add_unknown || add_a1) {