libgui: Remove custom BufferQueue allocators

Removes the ability to set a custom GraphicBuffer allocator for a
BufferQueue. Custom-allocated buffers may still be used through the
attachBuffer call.

Change-Id: I127bdfb496fc089a61c7e266c8bd2b906d41f32e
diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h
index 09300a2..c48ffb4 100644
--- a/include/gui/BufferQueue.h
+++ b/include/gui/BufferQueue.h
@@ -76,8 +76,7 @@
     // producers and consumers. allocator is used to allocate all the
     // needed gralloc buffers.
     static void createBufferQueue(sp<IGraphicBufferProducer>* outProducer,
-            sp<IGraphicBufferConsumer>* outConsumer,
-            const sp<IGraphicBufferAlloc>& allocator = NULL);
+            sp<IGraphicBufferConsumer>* outConsumer);
 
 private:
     BufferQueue(); // Create through createBufferQueue