Update Travis CI config to use Xenial

The default of Trusty is failing to find libsystemd-dev.

diff --git a/.travis.yml b/.travis.yml
index 064fb4fa9fd9d9a4e2b5a5c14186a298558bb4cf..9fee020f97144188732675fb5d7b1de39328bc48 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 language: c
+dist: xenial
 compiler:
   - clang
   - gcc