Don't try to fetch bridge descriptors when DisableNetwork is set

Patch from Roger; changes file by me.

Fixes 10405; bugfix on 0.2.3.9-alpha, where DisableNetwork was
introduced.

changes/bug10405

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Avoid "Tried to open a socket with DisableNetwork set" warnings
+      when starting a bridge client without bridge descriptors. Fixes
+      bug 10405; bugfix on 0.2.3.9-alpha.

src/or/main.c

@@ -1247,7 +1247,7 @@ run_scheduled_events(time_t now)
       now + DESCRIPTOR_FAILURE_RESET_INTERVAL;
   }
 
-  if (options->UseBridges)
+  if (options->UseBridges && !options->DisableNetwork)
     fetch_bridge_descriptors(options, now);
 
   /* 1b. Every MAX_SSL_KEY_LIFETIME_INTERNAL seconds, we change our