tools: Remove obsolete check-for-missing script

The script was used by a distcheck hook to check for files that are
in git, but not the distributed tarball. We dropped autotools support,
so the script is no longer used - in fact, it isn't useful anymore,
as `ninja dist` generates tarballs from git itself rather than from
a separately maintained list of files ...

tools/check-for-missing.py

@@ -1,26 +0,0 @@
-#!/usr/bin/python3
-#
-# This is a simple script that we use to check for files in git
-# and not in the distribution. It was previously written in shell
-# and inlined in the Makefile.am, but 'git ls-files --exclude=<pattern>'
-# was changed to no longer do anything useful, which made that
-# too challenging to be worthwhile.
-
-import fnmatch, os, subprocess, sys
-
-srcdir=sys.argv[1]
-distdir=sys.argv[2]
-excludes=sys.argv[3:]
-
-cwd=os.getcwd()
-os.chdir(srcdir)
-
-status=0
-for f in subprocess.Popen(["git", "ls-files"], stdout=subprocess.PIPE).stdout:
-    f = f.decode('utf-8').strip()
-    if (not os.path.exists(os.path.join(cwd, distdir, f)) and
-        not any((fnmatch.fnmatch(f, p) for p in excludes))):
-        print("File missing from distribution:", f)
-        status=1
-
-sys.exit(status)