Add volume drivers for Infortrend Storage

Add volume drivers for Infortrend Storage

Infortrend implement ISCSI and FC volume drivers for
EonStor DS product.
It manages storage by Infortrend CLI tool.

common_cli.py implements the basic Cinder Driver API.
infortrend_fc_cli.py and infortrend_iscsi_cli.py use them to
provide FC and iSCSI specific support.

Support features:
- Volume Create/Delete
- Volume Attach/Detach
- Snapshot Create/Delete
- Create Volume from Snapshot
- Get Volume Stats
- Copy Image to Volume
- Copy Volume to Image
- Clone Volume
- Extend Volume

Change-Id: I830c5a48a5fb85707f02396b4634825e27455e8a
Implements: blueprint infortrend-iscsi-fc-volume-driver