[R3.2 vcenter_only]fab setup_vcenter failing due to wait_for_task timing issue

[aswani kumar]

R3.2 vcenter_only build 16
fab setup_vcentr is failing with following error
File "/root/fabric-utils/fabfile/tasks/vcenter_prov.py", line 508, in __init__
2018-01-05 22:44:53:763715: self.configure_hosts_on_dvSwitch(self.vcenter_base.service_instance, network_folder, self.clusters, self.dvswitch_name)
2018-01-05 22:44:53:763857: File "/root/fabric-utils/fabfile/tasks/vcenter_prov.py", line 727, in configure_hosts_on_dvSwitch
2018-01-05 22:44:53:763888: self.vcenter_base.wait_for_task(task,si)
2018-01-05 22:44:53:764063: File "/root/fabric-utils/fabfile/tasks/vcenter_prov.py", line 40, in wait_for_task
2018-01-05 22:44:53:764093: raise ValueError(out)
2018-01-05 22:44:53:764151: ValueError: Error - 'vim.ServiceInstance:ServiceInstance' did not complete successfully: (vim.fault.ConcurrentAccess) {
2018-01-05 22:44:53:764225: dynamicType = <unset>,
2018-01-05 22:44:53:764225: dynamicProperty = (vmodl.DynamicProperty) [],
2018-01-05 22:44:53:764225: msg = 'Cannot complete operation due to concurrent modification by another operation.',
2018-01-05 22:44:53:764225: faultCause = <unset>,
2018-01-05 22:44:53:764225: faultMessage = (vmodl.LocalizableMessage) []

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/38815
Submitter: aswani kumar (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/38815
Committed: http://github.com/Juniper/contrail-fabric-utils/commit/69ff73ccd583b3b6ae76741e7291ce103bdb9e6e
Submitter: Zuul (<email address hidden>)
Branch: R3.2

commit 69ff73ccd583b3b6ae76741e7291ce103bdb9e6e
Author: Aswani Kumar Reddy G <email address hidden>
Date: Thu Jan 11 16:33:34 2018 +0530

Fix for setup_vcenter timing isssue and disable maintenance mode in esxi if enabled

Change-Id: I206cff2e55298c7505859df2623df59b0ff4d34e
Closes-Bug: #1742664