i965: Fix occlusion query when no other WM state updates occur.
i965: Fix occlusion query when no other WM state updates occur.

Turns out that XXX comment was important.  We weren't flagging the WM to
re-update with the statistics enable, so we got zeroes out of our query.

Bug #20740, fixes piglit occlusion_query test.

Signed-off-by: Eric Anholt <96f164ad4d9b2b0dacf8ebee2bb1eeb3aa69adf1@anholt.net>

bkaradzic/glsl-optimizer,mapbox/glsl-optimizer,wolf96/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,adobe/glsl2agal,metora/MesaGLSLCompiler,wolf96/glsl-optimizer,adobe/glsl2agal,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,adobe/glsl2agal,bkaradzic/glsl-optimizer,adobe/glsl2agal,tokyovigilante/glsl-optimizer,KTXSoftware/glsl2agal,zz85/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,tokyovigilante/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,KTXSoftware/glsl2agal,mcanthony/glsl-optimizer,zz85/glsl-optimizer,metora/MesaGLSLCompiler,wolf96/glsl-optimizer,zeux/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,KTXSoftware/glsl2agal,tokyovigilante/glsl-optimizer,KTXSoftware/glsl2agal,zeux/glsl-optimizer,benaadams/glsl-optimizer,zz85/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,bkaradzic/glsl-optimizer,djreep81/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,zeux/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer