mesa/glsl: stop using GL shader type internally

Instead use the internal gl_shader_stage enum everywhere. This
makes things more consistent and gets rid of unnecessary
conversions.

Ideally it would be nice to remove the Type field from gl_shader
altogether but currently it is used to differentiate between
gl_shader and gl_shader_program in the ShaderObjects hash table.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/compiler/glsl/standalone.cpp

@@ -418,7 +418,7 @@ standalone_compile_shader(const struct standalone_options *_options,
             continue;
 
          shader->Program = rzalloc(shader, gl_program);
-         init_gl_program(shader->Program, shader->Type);
+         init_gl_program(shader->Program, shader->Stage);
       }
    }