Bug 9754: koha-remove optionally includes var/lib and var/spool

 Bug 9754: koha-remove optionally includes var/lib and var/spool

Currently, the files in the folder /var/lib/koha/[instance] and also
in /var/spool/koha/[instance] are not removed.
This patch adds the option -p|--purge-all to include those two
directories when removing files.

Note: There was a small bug in the for loop. On the -k line the extra
shift statement is one too much.

NOTE: Verify that you use the adjusted koha-remove in the test plan
and not accidentally an older version of this script.

Test plan:
[1] Create an instance test.
[2] Run koha-remove and verify that /var/lib/koha/test still exists.
[3] Create an instance test2.
[4] Run koha-remove -k -p and verify that the sql database still exists
    but the two instance folders in var/lib/koha and var/spool/koha are
    gone.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>