When downloading bridge descs from a bridge authority, always be anonymous

changes/bug1938

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - When fetching a bridge descriptor from a bridge authority,
+      always do so anonymously, whether we have been able to open
+      circuits or not. Partial fix for bug 1938; bugfix on 2.0.7-alpha.

src/or/directory.c

@@ -130,8 +130,9 @@ purpose_needs_anonymity(uint8_t dir_purpose, uint8_t router_purpose)
 {
   if (get_options()->AllDirActionsPrivate)
     return 1;
-  if (router_purpose == ROUTER_PURPOSE_BRIDGE && can_complete_circuit)
-    return 1; /* if no circuits yet, we may need this info to bootstrap. */
+  if (router_purpose == ROUTER_PURPOSE_BRIDGE)
+    return 1; /* if no circuits yet, this might break bootstrapping, but it's
+               * needed to be safe. */
   if (dir_purpose == DIR_PURPOSE_UPLOAD_DIR ||
       dir_purpose == DIR_PURPOSE_UPLOAD_VOTE ||
       dir_purpose == DIR_PURPOSE_UPLOAD_SIGNATURES ||