tools: remove src/tools/codelines

This is a one-line script never gained general usage since being added
in 2005.

Backpatch-through: master

src/tools/codelines

@@ -1,7 +0,0 @@
-#!/bin/sh
-
-# src/tools/codelines
-
-# This script is used to compute the total number of "C" lines in the release
-# This should be run from the top of the Git tree.
-git ls-files -- '*.[chyl]' | xargs cat | wc -l