Fix GLES2 crash on Android when device be reseted.
Fix GLES2 crash on Android when device be reseted.

paroj/ogre,OGRECave/ogre,paroj/ogre,paroj/ogre,RealityFactory/ogre,OGRECave/ogre,RealityFactory/ogre,OGRECave/ogre,paroj/ogre,RealityFactory/ogre,OGRECave/ogre,RealityFactory/ogre,paroj/ogre,RealityFactory/ogre,OGRECave/ogre