Protect release script against non dist files.

On some OSes, for example OS X / macOS, if the dist/ folder is opened in
the GUI while during the build process, hidden files will be created,
and thus attempted to be uploaded.

This protect about that by restricting upload to tgz and whl files.

tools/release

@@ -6,6 +6,7 b' This should ONLY be run at real release time.'
 from __future__ import print_function
 
 import os
+from glob import glob
 from subprocess import call
 import sys
 
@@ -49,9 +50,10 b' cd(tooldir)'
 
 if 'upload' in sys.argv:
     cd(distdir)
-    #print( 'Uploading distribution files to GitHub...')
 
-    for fname in os.listdir('.'):
+    # do not upload OS specific files like .DS_Store
+    to_upload = glob('*.whl')+glob('*.tgz')
+    for fname in to_upload:
         # TODO: update to GitHub releases API
         continue
         print('uploading %s to GitHub' % fname)
@@ -61,7 +63,7 b" if 'upload' in sys.argv:"
     # Make target dir if it doesn't exist
     print('1. Uploading IPython to archive.ipython.org')
     sh('ssh %s "mkdir -p %s/release/%s" ' % (archive_user, archive_dir, version))
-    sh('scp * %s' % release_site)
+    sh('scp *.tgz *.whl %s' % release_site)
 
     print('2. Uploading backup files...')
     cd(ipbackupdir)
@@ -69,7 +71,7 b" if 'upload' in sys.argv:"
 
     print('3. Uploading to PyPI using twine')
     cd(distdir)
-    call(['twine', 'upload'] + os.listdir('.'))
+    call(['twine', 'upload'] + to_upload)
 
 else:
     # Build, but don't upload