fix the travis build for PHP-5.6 using precise instead of trusty

Tyrael · Tyrael · commit 787e3a1ee43b · 2017-10-25T01:51:48.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,4 @@
-dist: trusty
+dist: precise
 language: c
 sudo: false
 addons:
