Bug 25360: Use secure flag for CGISESSID cookie when using HTTPS

Bug 25360: Use secure flag for CGISESSID cookie when using HTTPS

This patch adds the secure flag to the CGISESSID cookie when using HTTPS.
This prevents the cookie being used again over a normal HTTP
request.

Bug 25360: [Follow-up] Test for "on" or "ON" value for HTTPS env var

This patch tests for HTTPS "on" or "ON" before setting the secure
cookie.

Bug 25360: [Follow-up] Fix typo in C4/InstallAuth.pm

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
[EDIT] Amended number of tests in Context.t
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>