Add the location of hvmloader to the search path

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
update-mh-info is important for changing management interface

So it shouldn't just fail.

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>
Merge pull request #571 from jonludlam/hvmloader-path

Add the location of hvmloader to the search path