Jessie fixes

xenstored is actually started by the 'xen' init script
uuidgen isn't installed by default
Merge pull request #469 from BobBall/xenstored-fix

Jessie fixes
Revert 59b6ff4db88e500480f502b9cdf17274601bbe34; was Ubuntu specific
Merge pull request #471 from BobBall/xenstored-fix

Revert 59b6ff4db88e500480f502b9cdf17274601bbe34; was Ubuntu specific
Update xenserver-install-wizard