http: adjust unit test to multirage changes

Acked-by: Paul Millar
Target: master, 2.8, 2.7, 2.6
Require-book: no
Require-notes: no
(cherry picked from commit a000a7301b9ef31bfc35d184d367bf98f3344784)
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>