Fixed an issue introduced by last change on the filter post processor when disabling all filters before the Processor is initialized

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10920 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core/com/jme3/post/FilterPostProcessor.java

@@ -361,7 +361,7 @@ public class FilterPostProcessor implements SceneProcessor, Savable {
                 return;
             }
         }
-        if (lastFilterIndex == -1) {
+        if (isInitialized() && lastFilterIndex == -1) {
             //There is no enabled filter, we restore the original framebuffer 
             //to the viewport to bypass the fpp.
             viewPort.setOutputFrameBuffer(outputBuffer);