vbo: rename vbo_save_primitive_store::buffer to prims

A little easier to understand.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/mesa/vbo/vbo_save.h

@@ -114,7 +114,7 @@ struct vbo_save_vertex_store {
 };
 
 struct vbo_save_primitive_store {
-   struct _mesa_prim buffer[VBO_SAVE_PRIM_SIZE];
+   struct _mesa_prim prims[VBO_SAVE_PRIM_SIZE];
    GLuint used;
    GLuint refcount;
 };

src/mesa/vbo/vbo_save_api.c

@@ -310,7 +310,7 @@ _save_reset_counters(struct gl_context *ctx)
 {
    struct vbo_save_context *save = &vbo_context(ctx)->save;
 
-   save->prim = save->prim_store->buffer + save->prim_store->used;
+   save->prim = save->prim_store->prims + save->prim_store->used;
    save->buffer = save->vertex_store->buffer + save->vertex_store->used;
 
    assert(save->buffer == save->buffer_ptr);