Bug 956374 - HTTP cache v2: fix CacheIOThread::Target() wait conditioning, r=michal

netwerk/cache2/CacheIOThread.cpp

@@ -114,12 +114,14 @@ void CacheIOThread::ThreadFunc()
     MonitorAutoLock lock(mMonitor);
 
     // This creates nsThread for this PRThread
-    mXPCOMThread = NS_GetCurrentThread();
+    nsCOMPtr<nsIThread> xpcomThread = NS_GetCurrentThread();
 
-    threadInternal = do_QueryInterface(mXPCOMThread);
+    threadInternal = do_QueryInterface(xpcomThread);
     if (threadInternal)
       threadInternal->SetObserver(this);
 
+    mXPCOMThread.swap(xpcomThread);
+
     lock.NotifyAll();
 
     do {