Merge pull request xapi-project#2402 from djs55/release.1.9.80

Prepare to release 1.9.80

Merge pull request xapi-project#2341 from djs55/release.1.9.70

Prepare to release 1.9.70

Merge pull request xapi-project#2203 from djs55/release.1.9.60

Prepare to release 1.9.60

Merge pull request xapi-project#2024 from djs55/release.1.9.58

Release 1.9.58

Merge pull request xapi-project#1996 from johnelse/rrdd-plugin-interface

Handle Rrdd_plugin interface change

Merge pull request xapi-project#1943 from djs55/release.1.9.56

Release 1.9.56

Merge pull request xapi-project#1940 from djs55/release.1.9.55

Release 1.9.55

Merge pull request xapi-project#1938 from djs55/release.1.9.54

Release 1.9.54

Merge pull request xapi-project#1923 from djs55/release-1.9.53

Release 1.9.53

Merge pull request xapi-project#1850 from jonludlam/ocaml-4.00.1-buil…

…d-fix

Fix build on ocaml-4.00.1