RHV : Host Upgrade fails to connect to NFS storage domain.

Issue

• RHV hosts were upgraded via GUI after which it fails to activate and keeps reporting as Non-Operational.
• RHV failed to mount NFS storage domain and reported errors as follows

Engine.log

2017-09-07 17:14:29,988+03 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler7) [11ea445e] EVENT_ID: VDS_STORAGES_CONNECTION_FAILED(188), Correlation ID: null, Call Stack: null, Custom Event ID: -1, Message: Failed to connect Host redhat-host1 to the Storage Domains data,os.
2017-09-07 17:14:29,988+03 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ConnectStorageServerVDSCommand] (DefaultQuartzScheduler7) [11ea445e] FINISH, ConnectStorageServerVDSCommand, return: {2d42a5c4-043f-47a0-ac99-65a6b00d51d4=477, 894f6967-8ca1-4abe-8e06-26f041089486=477, 1b201c5d-f1de-474f-8f50-f66d90280c9e=0, 00579346-be6a-44f2-a4b0-b508990315c5=0}, log id: 3ffb98f2
2017-09-07 17:14:29,991+03 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler7) [11ea445e] EVENT_ID: STORAGE_DOMAIN_ERROR(996), Correlation ID: null, Call Stack: null, Custom Event ID: -1, Message: The error message for connection 192.168.1.xx:/root_vdm_2/rhv_bre_data returned by VDSM was: Problem while trying to mount target
2017-09-07 17:14:29,992+03 ERROR [org.ovirt.engine.core.bll.storage.connection.BaseFsStorageHelper] (DefaultQuartzScheduler7) [11ea445e] The connection with details '192.168.1.xx:/root_vdm_2/rhv_bre_data' failed because of error code '477' and error message is: problem while trying to mount target
2017-09-07 17:14:29,996+03 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler7) [11ea445e] EVENT_ID: STORAGE_DOMAIN_ERROR(996), Correlation ID: null, Call Stack: null, Custom Event ID: -1, Message: The error message for connection 192.168.1.xx:/root_vdm_2/rhv_bre_os returned by VDSM was: Problem while trying to mount target
2017-09-07 17:14:29,996+03 ERROR [org.ovirt.engine.core.bll.storage.connection.BaseFsStorageHelper] (DefaultQuartzScheduler7) [11ea445e] The connection with details '192.168.1.xx:/root_vdm_2/rhv_bre_os' failed because of error code '477' and error message is: problem while trying to mount target
2017-09-07 17:14:29,999+03 INFO  [org.ovirt.engine.core.bll.storage.pool.ConnectHostToStoragePoolServersCommand] (DefaultQuartzScheduler7) [11ea445e] Host 'redhat-host1' storage connection was failed 
2017-09-07 17:14:30,002+03 WARN  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (DefaultQuartzScheduler7) [11ea445e] EVENT_ID: CONNECT_STORAGE_SERVERS_FAILED(994), Correlation ID: 11ea445e, Call Stack: null, Custom Event ID: -1, Message: Failed to connect Host redhat-host1 to Storage Servers

vdsm.log

2017-09-07 17:14:24,868+0300 INFO  (jsonrpc/3) [storage.Mount] mounting 192.168.1.xx:/root_vdm_2/rhv_bre_data at /rhev/data-center/mnt/192.168.1.xx:_root__vdm__2_rhv__bre__data (mount:187)
2017-09-07 17:14:24,972+0300 ERROR (jsonrpc/3) [storage.HSM] Could not connect to storageServer (hsm:2385)
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/hsm.py", line 2382, in connectStorageServer
    conObj.connect()
  File "/usr/share/vdsm/storage/storageServer.py", line 381, in connect
    return self._mountCon.connect()
  File "/usr/share/vdsm/storage/storageServer.py", line 163, in connect
    six.reraise(t, v, tb)
  File "/usr/share/vdsm/storage/storageServer.py", line 155, in connect
    self._mount.mount(self.options, self._vfsType, cgroup=self.CGROUP)
  File "/usr/lib/python2.7/site-packages/vdsm/storage/mount.py", line 190, in mount 
    timeout=timeout, cgroup=cgroup)
  File "/usr/lib/python2.7/site-packages/vdsm/supervdsm.py", line 53, in __call__
    return callMethod()
  File "/usr/lib/python2.7/site-packages/vdsm/supervdsm.py", line 51, in <lambda>
    **kwargs)
  File "<string>", line 2, in mount
  File "/usr/lib64/python2.7/multiprocessing/managers.py", line 773, in _callmethod
    raise convert_to_error(kind, result)
MountError: (32, ';mount.nfs: Operation not permitted\n')