Make patchlevel print out the release if called as a script.

Doc/tools/sphinxext/patchlevel.py

@@ -66,3 +66,6 @@ def get_version_info():
         print >>sys.stderr, 'Can\'t get version info from Include/patchlevel.h, ' \
               'using version of this interpreter (%s).' % release
         return version, release
+
+if __name__ == '__main__':
+    print get_header_version_info('.')[1]