Roll _mesa_free_parameters() into calling function (the only caller).

Replace assert(0) with _mesa_warning().
Use new _mesa_align_realloc() function.
New comments, clean-ups.

src/mesa/shader/program.h

@@ -222,9 +222,6 @@ _mesa_new_parameter_list(void);
 extern void
 _mesa_free_parameter_list(struct program_parameter_list *paramList);
 
-extern void
-_mesa_free_parameters(struct program_parameter_list *paramList);
-
 extern GLint
 _mesa_add_named_parameter(struct program_parameter_list *paramList,
                           const char *name, const GLfloat values[4]);