DRMDisplay: Restore previous framebuffer on shutdown

src/common/gl/context_egl_gbm.cpp

@@ -21,6 +21,8 @@ ContextEGLGBM::~ContextEGLGBM()
   Assert(!m_current_present_buffer);
 #endif
 
+  m_drm_display.RestoreBuffer();
+
   // We have to destroy the context before the surface/device.
   // Leaving it to the base class would be too late.
   DestroySurface();