e2e: remove passing waitgroups reference for go routines
e2e: remove passing waitgroups reference for go routines

We are unwantedly passing around waitgroups which is not required.
This address the same inside e2e/rbd_helper.go and remove the waitgroup
arg

Signed-off-by: Humble Chirammal <dc8ba7e82a7df22725dedec9b10c7aaab9ec713f@redhat.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi