tests: replaced fedora:rawhide with fedora:26
tests: replaced fedora:rawhide with fedora:26

Signed-off-by: Lior Haim <95c7608050b0653f18b44b35d1172b7bd153b32c@daynix.com>

rbld/rebuild,rbld/rebuild,rbld/rebuild,daynix/rebuild,daynix/rebuild,daynix/rebuild