VMware driver: Uses deprecated RetrieveProperties API

[Kartik Bommepally]

VMware drivers uses deprecated RetrieveProperties API while talking to PropertyCollector.
Apart from being a deprecated API, it has issues when working with large environments.
Trying to retrieve information such as all the VMs or hosts in the inventory in one shot can end up eating lot of network resources and may hang the service.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47130

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47130
Committed: http://github.com/openstack/cinder/commit/010fe685e50a3680d8c8b9b6602677df90e815b3
Submitter: Jenkins
Branch: master

commit 010fe685e50a3680d8c8b9b6602677df90e815b3
Author: Kartik Bommepally <email address hidden>
Date: Mon Sep 16 03:23:23 2013 -0700

    VMware: Usng RetrvProprtisEx & does multi ESX scan

    The existing code uses deprecated API RetrieveProperties for querying through
    property collector. The public doc asks to use RetrievePropertiesEx instead.

    RetrievePropertiesEx works by retrieving results in serveral batches rather than
    retrieval in a single API call. This works well in environments containing
    large number of VMs or ESX hosts.

    There are three steps involved 1. Get first batch 2. Continue retrieving using
    a token 3. Cancel retrieval when not needed

    Batch size is user configurable, default is 100 results per batch.

    The review also fixes a careless programming error leading to scanning only
    1 ESX host under the vCenter server for datastores.

    Fixes bug: 1227078
    Fixes bug: 1229654
    DocImpact

    Change-Id: I85a6f6a7e2d764b9843efbd0dd347fba3ef19310