Description of problem:

I could not set SHE host - 3.6 RHEVH-EL7 20160711.0.el7ev - whic was part of SHE env with 4.0 NGN host to maintenance.

I saw a lot of:

~~~
Thread-100746::ERROR::2016-08-09 10:38:47,615::task::866::Storage.TaskManager.Task::(_setError) Task=`d890728d-a9cd-4ad6-92b1-c3899995eadb`::Unexpected error
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/task.py", line 873, in _run
    return fn(*args, **kargs)
  File "/usr/share/vdsm/logUtils.py", line 49, in wrapper
    res = f(*args, **kwargs)
  File "/usr/share/vdsm/storage/hsm.py", line 3673, in stopMonitoringDomain
    raise se.StorageDomainIsMemberOfPool(sdUUID)
StorageDomainIsMemberOfPool: Storage domain is member of pool: 'domain=cf7a884b-b0f0-4d41-aa86-c3aca18c43fc'
Thread-100746::DEBUG::2016-08-09 10:38:47,615::task::885::Storage.TaskManager.Task::(_run) Task=`d890728d-a9cd-4ad6-92b1-c3899995eadb`::Task._run: d890728d-a9cd-4ad6-92b1-c3899995eadb ('cf7a884b-b0f0-4d41-aa86-c3
aca18c43fc',) {} failed - stopping task
~~~

Version-Release number of selected component (if applicable):
4.17

How reproducible:
right now

Steps to Reproduce:
1. have SHE env with FC luns - one 3.6  RHEVH with 3.6 engine
2. add 4.0 NGN
3. hosted-engine --upgrade-appliance to upgrade engine to 4.0
4. hosted-engine --set-maintenance --mode=local on 3.6 RHEVH
5. when engine runs on NGN, move 3.6 RHEVH into maintenance

Actual results:
stucked in preparing to maintenance

Expected results:


Additional info: