mesa: dont call _mesa_override_glsl_version() in _mesa_init_constants()

All drivers that support GLSL will later set their default GLSL versions
overriding this override call. They currently all call
 _mesa_override_glsl_version() again later in order to support overrides.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/mesa/main/context.c

@@ -638,9 +638,6 @@ _mesa_init_constants(struct gl_constants *consts, gl_api api)
    consts->MaxGeometryOutputVertices = MAX_GEOMETRY_OUTPUT_VERTICES;
    consts->MaxGeometryTotalOutputComponents = MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS;
 
-   /* Shading language version */
-   _mesa_override_glsl_version(consts);
-
 #ifdef DEBUG
    consts->GenerateTemporaryNames = true;
 #else