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
(cherry picked from commit 0c9dc5d0e01576969f09edc0c9c72a2aa91b248a)
Merge "Support Huawei driver upgrade from grizzly to havana" into milestone-proposed