switch to trusty beta dist

jefferis · jefferis · commit fdf6eeed6c7a · 2017-04-20T22:13:24.000+01:00
* in hopes this will fix rvcg compile issue
diff --git a/.travis.yml b/.travis.yml
@@ -2,6 +2,7 @@
 
 language: R
 sudo: false
+dist: trusty
 cache:
   packages: true
   directories:
