More recent linux distro required for modern nodejs in travis [ci skip]

.travis.yml

-language: c
+language: node_js
 sudo: required
+dist: trusty
 
-install:
-  - wget https://raw.githubusercontent.com/ocaml/ocaml-ci-scripts/master/.travis-ocaml.sh
-  - bash -ex .travis-ocaml.sh
-  - make init
-  - if [[ -v TESTJSJSREF ]]; then make test_init; fi
-  - eval `opam config env`
-
-script:
-  - make
-  - if [[ -v TESTJSJSREF ]]; then make test; fi
+# a reasonably recent node is required to run tests, it depends on
+node_js:
+  - "4"
 
 env:
   global:
     - OCAML_VERSION=4.03
     - OPAMYES=true
+    - UBUNTU_TRUSTY=1
 
 matrix:
   include:
@@ -25,6 +20,18 @@ matrix:
       env: DEPLOY=true
     - os: osx
 
+
+install:
+  - wget https://raw.githubusercontent.com/ocaml/ocaml-ci-scripts/master/.travis-ocaml.sh
+  - bash -ex .travis-ocaml.sh
+  - make init
+  - if [[ -v TESTJSJSREF ]]; then make test_init; fi
+  - eval `opam config env`
+
+script:
+  - make
+  - if [[ -v TESTJSJSREF ]]; then make test; fi
+
 deploy:
   skip_cleanup: true
   provider: script