xen-api-init: OCAMLRUNPARAM needs to be exported

Signed-off-by: Euan Harris <euan.harris@citrix.com>
Merge pull request #150 from euanh/openstack-fixes

xen-api-init: OCAMLRUNPARAM needs to be exported
Merge pull request #151 from euanh/build-improvements

xapi: Remove commented-out %patch call