Bug 25538: Use sudo -i in koha-shell

Bug 25538: Use sudo -i in koha-shell

See man sudo, -i parameter.
Should we expect regressions?

Test plan:
0. Use D11 or U18.
Don't apply this patch
1.
$ echo $KOHA_INTRANET_URL
$ sudo koha-shell kohadev
$ echo $KOHA_INTRANET_URL
2. Apply this patch
$ cp debian/scripts/koha-shell /usr/sbin/koha-shell
3. Repeat 1.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>