dispersed_glusterfs and replicated_glusterfs _get_hashrange error when do dht's some test case

[yindakuikui]

for example, do command " glusto -c /root/glusto-tests/tests/test.yml --pytest='-v -s dht/test_volume_start_stop_while_rebalance_in_progress.py::RebalanceValidation_cplex_dispersed_glusterfs::test_volume_start_stop_while_rebalance_is_in_progress' " will get hash error. The reason is that the dispersed and replicated volume's mountpoint xattr don't have hashrange when we do command getfattr -dm . -e hex mountpoint.