mesa: Unbind deleted textures from the shader image units.
mesa: Unbind deleted textures from the shader image units.

From ARB_shader_image_load_store:

   If a texture object bound to one or more image units is deleted by
   DeleteTextures, it is detached from each such image unit, as though
   BindImageTexture were called with <unit> identifying the image unit
   and <texture> set to zero.

Reviewed-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>
Reviewed-by: Paul Berry <de21b9f22e6dd0bdf7890875d6e07ef4967c44ce@gmail.com>

jbarczak/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer,bkaradzic/glsl-optimizer,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,metora/MesaGLSLCompiler,tokyovigilante/glsl-optimizer,djreep81/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,dellis1972/glsl-optimizer,zz85/glsl-optimizer,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,dellis1972/glsl-optimizer,djreep81/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,djreep81/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,bkaradzic/glsl-optimizer,tokyovigilante/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,mapbox/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,zz85/glsl-optimizer,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,benaadams/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer