Laurent Bachelier authored Dec 21, 2018 and Romain Bignon committed Dec 29, 2018

Since we already generate the man pages automatically,
we can generate the bash completions too.
It is much faster and does not risk making any network requests.

fixes #194

For system installation, the bash auto-completion will display messages
for users without home directory. Redirect stderr to null

* Add files to the possibilities (needed at least for pastoob).
  For now show them only if nothing else  matches.
* Remove useless "$have" test that failed every time
* Forget fake "hash" after running
* Simpler code overall