Bug 11587 - IsSuperLibrarian generates warnings (UT)

Bug 11587 - IsSuperLibrarian generates warnings (UT)

Simply viewing OPAC detail triggers a modulus warning entry.
This first patch adds two test cases to t/Context.t to test for
this situation.

TEST PLAN
---------
1) Apply this patch (to upgrade t/Context.t)
2) prove -v t/Context.t
-- Tests 7 and 8 will fail
3) Apply main patch (to amend C4/Context.pm)
4) prove -v t/Context.t
-- All tests will succeed

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>