gl: remove extra dispatch entry for glRenderbufferStorageMultisample
gl:  THIS IS LIKE HACK.  Make msaa compositor works on HD3000/HD4000

Mesa 9.1+ supports GLESv3, but does not support GL_ANGLE_framebuffer_blit
and GL_ANGLE_framebuffer_multisample.  However, these two extensions
have been part of standard GLESv3 functions.  So if the driver supports
GLESv3, it is almost certain, it also supports these two extensions.