We only use the prev pointer

(Why not use a std::list? Maybe there is some reason.)

Change-Id: I09010726e9fe45cfa0f530a085c48ec8d3d02cfb

vcl/inc/opengl/framebuffer.hxx

@@ -41,7 +41,6 @@ public:
 
 public:
     OpenGLFramebuffer* mpPrevFramebuffer;
-    OpenGLFramebuffer* mpNextFramebuffer;
 };
 
 #endif // INCLUDED_VCL_INC_OPENGL_FRAMEBUFFER_H

vcl/opengl/framebuffer.cxx

@@ -18,8 +18,7 @@ OpenGLFramebuffer::OpenGLFramebuffer() :
     mnWidth( 0 ),
     mnHeight( 0 ),
     mnAttachedTexture( 0 ),
-    mpPrevFramebuffer( nullptr ),
-    mpNextFramebuffer( nullptr )
+    mpPrevFramebuffer( nullptr )
 {
     glGenFramebuffers( 1, &mnId );
     CHECK_GL_ERROR();

vcl/source/opengl/OpenGLContext.cxx

@@ -1649,7 +1649,6 @@ OpenGLFramebuffer* OpenGLContext::AcquireFramebuffer( const OpenGLTexture& rText
         if( mpLastFramebuffer )
         {
             pFramebuffer->mpPrevFramebuffer = mpLastFramebuffer;
-            mpLastFramebuffer->mpNextFramebuffer = pFramebuffer;
             mpLastFramebuffer = pFramebuffer;
         }
         else