Added fix for d3d9 textures by rogerborg- D3D9 textures no longer hold on to the IImage pointer, a copy is already in system ram due to using the d3d_managed pool. The same change should also be added to D3D8 textures.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1122 dfc29bdd-3216-0410-991c-e03cc46cb475