[GLES2] Fix floating point pixel formats
[GLES2] Fix floating point pixel formats

--HG--
branch : v1-8

jhu-lcsr-forks/ogre,jhu-lcsr-forks/ogre,jhu-lcsr-forks/ogre,jhu-lcsr-forks/ogre,vancepym/ogre,vancepym/ogre,jhu-lcsr-forks/ogre,vancepym/ogre,vancepym/ogre,vancepym/ogre