Fix clear_depth not working after drawing with depth_write = false
Fix clear_depth not working after drawing with depth_write = false

TyOverby/glium,rozaliev/glium,msiglreith/glium,carbidegames/glium,cpjreynolds/glium,bvssvni/glium,tomaka/glium,binsoftware/glium,sdotz/glium,acolley/glium,christopheraugustus/glium,nicokoch/glium,caldwell/glium,glium/glium