This will simply list the files in the current directory if there are no
auto-completion options available.
With this change, the zsh auto-completion will align with the functionality in
the bash auto-completion file provided.
New functionality: https://asciinema.org/a/EAYRIEVGTGNSS2gCGwSJ4Zw1i
Old functionality: https://asciinema.org/a/BfOZz4BHUGwjXMFptbmDHZocH
Signed-off-by: Ole Petter <ole.orhagen@northern.tech>
