Completion for executables is broken

Created by: huntergoldstein

Reproduction: Attempt to autocomplete an executable

Expected behavior:

$ ba<tab>
bacman     badblocks  baobab     base.py    base32     base64     basename   
bash       bashbug

Actual behavior:

$ ba<tab>
# nothing happens

Misc: I have confirmed that this bug was introduced in this commit, of which I am the author.