util: fix tracevol.py to manage config map created by Rook
util: fix tracevol.py to manage config map created by Rook

If the config map is created by rook then there won't be any provision to
specify subvolumeGroup, tracevol.py should skip looking for subvolumeGroup
in such case.

Signed-off-by: Mudit Agarwal <e5356c34e3b3b8ef2f9750bb431df6fcd5e2fa6e@redhat.com>

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