Support Huawei driver upgrade from grizzly to havana

To make the driver upgrade from grizzly to higher versions, the patch
checks the old host name firstly when creating and deleting host in
Huawei storage system.
If the old host name exists:
*get and use it directly when adding host.
*delete it directly when deleting host.

Closes-bug 1237189

Change-Id: I82a9dbc1ef0bb0b91771afea4aadec5afe65eecf
Merge "Support Huawei driver upgrade from grizzly to havana"