rbd: add tests for GetPoolMetadata() and SetPoolMetadata()
rbd: add tests for GetPoolMetadata() and SetPoolMetadata()

Added test cases for GetPoolMetadata() func and SetPoolMetadata() func.

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

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph