Revert "do not promote framebuffer override to global default"

This reverts commit 1603906.

Author: riccardobl

jme3-android/src/main/java/com/jme3/system/android/OGLESContext.java

@@ -686,6 +686,10 @@ private boolean renderFrameWithBlitSrgbConversion() {
         renderer.setMainFrameBufferOverride(linearFrameBuffer);
         try {
             listener.update();
+            FrameBuffer currentMainFramebuffer = renderer.getCurrentFrameBuffer();
+            if (currentMainFramebuffer != linearFrameBuffer) {
+                restoreMainFramebuffer = currentMainFramebuffer;
+            }
         } finally {
             renderer.setMainFrameBufferOverride(restoreMainFramebuffer);
         }

jme3-ios/src/main/java/com/jme3/system/ios/IGLESContext.java

@@ -480,6 +480,10 @@ private boolean renderFrameWithBlitSrgbConversion() {
         renderer.setMainFrameBufferOverride(linearFrameBuffer);
         try {
             listener.update();
+            FrameBuffer currentMainFramebuffer = renderer.getCurrentFrameBuffer();
+            if (currentMainFramebuffer != linearFrameBuffer) {
+                restoreMainFramebuffer = currentMainFramebuffer;
+            }
         } finally {
             renderer.setMainFrameBufferOverride(restoreMainFramebuffer);
         }

jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglWindow.java

@@ -865,6 +865,10 @@ private boolean renderFrameWithAuxFramebuffer() {
         glRenderer.setMainFrameBufferOverride(auxFramebuffer);
         try {
             listener.update();
+            FrameBuffer currentMainFramebuffer = renderer.getCurrentFrameBuffer();
+            if (currentMainFramebuffer != auxFramebuffer) {
+                restoreMainFramebuffer = currentMainFramebuffer;
+            }
         } finally {
             glRenderer.setMainFrameBufferOverride(restoreMainFramebuffer);
         }