Changelog:
===========
-Allow register-python-argcomplete output to be used as lazy-loaded zsh completion module
-Move debug_stream initialization to helper method to allow fd 9 behavior to be overridden in subclasses
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
