Update compiler in travis file

Signed-off-by: Rob Hoes <[email protected]>

Author: robhoes

.travis.yml

@@ -8,7 +8,7 @@ script:
 sudo: required
 env:
   global:
-    - OCAML_VERSION=4.02
+    - OCAML_VERSION=4.04
     - PACKAGE=xapi-idl
   matrix:
     - BASE_REMOTE=git://github.com/xapi-project/xs-opam XS_COV=1 COV_CONF="ocaml setup.ml -configure --enable-tests"