tests: fix broken symlink
tests: fix broken symlink

`requirements2.5.txt` is pointing to `tests/requirements2.4.txt` while
it should point to `requirements2.4.txt` since they are in the same
directory.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>
(cherry picked from commit 6f489015e44f8c10ea0ad47b23bada6ff8351f68)
Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

fgal/ceph-ansible,fgal/ceph-ansible