xen-evtchn.unix.activations needs to depend on xen-evtchn

This is because the Unix_activations module depends on Eventchn and
Generation.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #8 from djs55/dependency

Fix a dependency which allows ocaml-vchan to link