Remove unused sphinx-build.py entry script.

Doc/tools/sphinx-build.py

-# -*- coding: utf-8 -*-
-"""
-    Sphinx - Python documentation toolchain
-    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-    :copyright: 2007-2010 by Georg Brandl.
-    :license: Python license.
-"""
-
-import sys
-import warnings
-
-# Get rid of UserWarnings reported by pkg_resources.
-warnings.filterwarnings('ignore', category=UserWarning, module='jinja2')
-
-if __name__ == '__main__':
-
-    if sys.version_info[:3] < (2, 4, 0) or sys.version_info[:3] > (3, 0, 0):
-        sys.stderr.write("""\
-Error: Sphinx needs to be executed with Python 2.4 or newer (not 3.0 though).
-(If you run this from the Makefile, you can set the PYTHON variable
-to the path of an alternative interpreter executable, e.g.,
-``make html PYTHON=python2.5``).
-""")
-        sys.exit(1)
-
-    from sphinx import main
-    sys.exit(main(sys.argv))