Disable (Cell,DirReq,Entry,ExitPort)Statistics on bridges

These stats are currently discarded, but we might as well
hard-disable them on bridges, to be clean.

Fix for bug 5824; bugfix on 0.2.1.17-rc.

Patch originally by Karsten Loesing.

changes/bug5824

@@ -0,0 +1,3 @@
+  o Minor bugfixes:
+    - Bridges now never collect statistics that were designed for
+      relays. Fix for bug 5824; bugfix on 0.2.1.17-rc.

src/or/config.c

@@ -1703,8 +1703,9 @@ options_act(const or_options_t *old_options)
     time_t now = time(NULL);
     int print_notice = 0;
 
-    /* If we aren't acting as a server, we can't collect stats anyway. */
-    if (!server_mode(options)) {
+    /* If we aren't acting as a server, or we are a bridge, we can't collect
+     * stats anyway. */
+    if (!public_server_mode(options)) {
       options->CellStatistics = 0;
       options->DirReqStatistics = 0;
       options->EntryStatistics = 0;