renderer/native: Make the EGLStreams operate in mailbox mode

This means eglSwapBuffers() wont dead lock if there is an old buffer pending
page flip. This could happen after e.g. mode changes or for other reasons.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/485

src/backends/native/meta-renderer-native.c

@@ -2623,7 +2623,7 @@ meta_renderer_native_create_surface_egl_device (CoglOnscreen       *onscreen,
   EGLOutputLayerEXT output_layer;
   EGLAttrib output_attribs[3];
   EGLint stream_attribs[] = {
-    EGL_STREAM_FIFO_LENGTH_KHR, 1,
+    EGL_STREAM_FIFO_LENGTH_KHR, 0,
     EGL_CONSUMER_AUTO_ACQUIRE_EXT, EGL_FALSE,
     EGL_NONE
   };