Fix the conversion of textures to rendertargets to use the right number of mip levels if we already initialized storage. When a texture was initialized with glStorage2DEXT or similar, the conversion to RT could change the number of mips. TRAC #22560 Signed-off-by: Geoff Lang Signed-off-by: Nicolas Capens Author: Jamie Madill git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1894 736b8ea6-26fd-11df-bfd4-992fa37f6226