setup: don't import distutils prior to checking FORCE_SETUPTOOLS

I've seen warnings about importing distutils before setuptools,
although I can't reproduce them at the moment.

Differential Revision: https://phab.mercurial-scm.org/D9722

setup.py

@@ -179,7 +179,6 b' import stat, subprocess, time'
 import re
 import shutil
 import tempfile
-from distutils import log
 
 # We have issues with setuptools on some platforms and builders. Until
 # those are resolved, setuptools is opt-in except for platforms where
@@ -199,6 +198,7 b' from distutils.command.build_scripts imp'
 from distutils.command.install import install
 from distutils.command.install_lib import install_lib
 from distutils.command.install_scripts import install_scripts
+from distutils import log
 from distutils.spawn import spawn, find_executable
 from distutils import file_util
 from distutils.errors import (