Add an error check for an 'EQUOTA' response from xenstore and
translate it to STATUS_QUOTA_EXCEEDED.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Merge pull request #10 from pauldu/master

Add an error check for an 'EQUOTA' response from xenstore and

Approved-By: Ben Chalmers <ben.chalmers@citrix.com>