meta: Don't use fixed-function to decompress array textures

meta: Don't use fixed-function to decompress array textures

Array textures can't be used with fixed-function, so don't.  Instead,
just drop the decompress request on the floor.  This is no worse than
what was done previously because generating the GL error (in
_mesa_set_enable) broke everything anyway.

A later patch will get GL_TEXTURE_2D_ARRAY targets working.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>