Bug 12086: qa-followup: remove warning on launching unit tests

Bug 12086: qa-followup: remove warning on launching unit tests

Without this patch, the following warning appears:
  t/db_dependent/Holds/RevertWaitingStatus.t .. Subroutine
  C4::Context::userenv redefined at
  t/db_dependent/Holds/RevertWaitingStatus.t line 25.

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 8e1b6f76d60efd4b7806788ec44c73348dcbdd51)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>