glsl: Simplify symbol table version checking.

Previously, we stored the GLSL language version in the
glsl_symbol_table struct.  But this was unnecessary--all
glsl_symbol_table needs to know is whether functions and variables
have separate namespaces (they do in GLSL 1.10 only).

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Carl Worth <cworth@cworth.org>

src/glsl/ast_function.cpp

@@ -324,7 +324,8 @@ match_function_by_name(const char *name,
       goto done; /* no match */
 
    /* Is the function hidden by a variable (impossible in 1.10)? */
-   if (state->language_version != 110 && state->symbols->get_variable(name))
+   if (!state->symbols->separate_function_namespace
+       && state->symbols->get_variable(name))
       goto done; /* no match */
 
    if (f != NULL) {