XCP-XAPI version fix
XCP-XAPI version fix

Fixes bug 1033933.

On an Kronos installation (Ubuntu + XCP-XAPI), the reported
software_version dictionary did not contain both product_version and
product_brand. This caused a KeyError. With this fix, the session's
product_version and product_brand will default to None in such cases.
The resize operation's name in these cases will default to VDI.resize.

Change-Id: Ic0db4128a7b27c08c24461562423bcecd1373e58

n0ano/ganttclient