Global completion without bash defaults

[btjones0]

It looks like activate-global-python-argcomplete used to have a --no-defaults flag (similar to register-python-argcomplete) but this was removed when zsh support was added. Would it be possible to get this back for bash?

[evanunderscore]

For reference, the commit that removed it is here: https://github.com/kislyuk/argcomplete/commit/483a7454e33b7e4aa32d09aa6f11002968878e61

This flag should be added back and ideally also implemented in zsh (should be as simple as conditionally calling _default when no matches are returned if there isn't an equivalent flag).