Use opam-repo-dev from xapi-project for travis
Use opam-repo-dev from xapi-project for travis

Signed-off-by: Jon Ludlam <e7e3380887a8f95cc9dc4f0d51dedc7e849a287a@citrix.com>

xapi-project/message-switch,xapi-project/message-switch,johnelse/forkexecd,xapi-project/message-switch