sdist_upip: Need to override setuptools' "sdist" command, not distutils'.

Without setuptools, there will be no goodies like dependencies, etc.

Author: pfalcon

sdist_upip.py

@@ -21,7 +21,7 @@
 import io
 
 from distutils.filelist import FileList
-from distutils.command.sdist import sdist as _sdist
+from setuptools.command.sdist import sdist as _sdist
 
 
 def gzip_4k(inf, fname):