surfaceflinger: unlock clients only after flip

Change-Id: I039291a36f05bbaa02b29325d4012114abd784b9
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index a78d9b9..83f96a6 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -383,10 +383,10 @@
         // inform the h/w that we're done compositing
         hw.compositionComplete();
 
-        // release the clients before we flip ('cause flip might block)
+        postFramebuffer();
+
         unlockClients();
 
-        postFramebuffer();
     } else {
         // pretend we did the post
         unlockClients();