Replace gl_vert_result enum with gl_varying_slot.

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

gl_vert_result -> gl_varying_slot
VERT_RESULT_* -> VARYING_SLOT_*

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Brian Paul <brianp@vmware.com>
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 57e7a9a..adcfda8 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1777,7 +1777,7 @@
    if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
       link_invalidate_variable_locations(
             prog->_LinkedShaders[MESA_SHADER_VERTEX],
-            VERT_ATTRIB_GENERIC0, VERT_RESULT_VAR0);
+            VERT_ATTRIB_GENERIC0, VARYING_SLOT_VAR0);
    }
    /* FINISHME: Geometry shaders not implemented yet */
    if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {