[docs] [issue13402] Document absoluteness of sys.executable

Petri Lehtinen <petri@digip.org> added the comment: Attaching an updated patch. The documentation now says that sys.executable may be an empty string. The patch also adds a test to make sure that sys.executable is absolute. ---------- Added file: http://bugs.python.org/file23958/issue13402_v2.patch _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue13402> _______________________________________