Bug 17467: Add tab-completion for koha-zebra

Bug 17467: Add tab-completion for koha-zebra

This patch adds tab-completion for bash, for the koha-zebra script.

To test:
- Run (on the vagrant user):
  $ source kohaclone/debian/koha-common.bash-completion
- Run:
  $ sudo koha-zebra -<TAB>
  (<TAB> means press the tab key)
=> SUCCESS: Tab completion works as expected for the koha-zebra command.
- Sign off :-D

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>