Replace gl_geom_result enum with gl_varying_slot.

This patch makes the following search-and-replace changes:

gl_geom_result -> gl_varying_slot
GEOM_RESULT_* -> VARYING_SLOT_*

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Brian Paul <brianp@vmware.com>

src/mesa/main/context.c

@@ -349,7 +349,6 @@ dummy_enum_func(void)
    gl_texture_index ti = TEXTURE_2D_ARRAY_INDEX;
    gl_vert_attrib va = VERT_ATTRIB_POS;
    gl_varying_slot vs = VARYING_SLOT_POS;
-   gl_geom_result gr = GEOM_RESULT_POS;
 
    (void) bi;
    (void) fi;
@@ -358,7 +357,6 @@ dummy_enum_func(void)
    (void) ti;
    (void) va;
    (void) vs;
-   (void) gr;
 }