Initialize fixed texture with previous data.

git-svn-id: https://www.williamfeely.info/svn/dxgl@476 8a90861a-4eca-46d5-b744-240ff16d0c4d
Deinitialize FBO when repairing texture.

git-svn-id: https://www.williamfeely.info/svn/dxgl@477 8a90861a-4eca-46d5-b744-240ff16d0c4d