Reinstate RELEASE

Jobs depend on this value to write to the correct config file

Author: BanzaiMan

.travis.yml

@@ -5,6 +5,8 @@ matrix:
     - sudo: required
       dist: xenial
       group: edge
+      env:
+        - RELEASE=xenial
       name: xenial
       php: '5.6'
       before_install:
@@ -26,18 +28,24 @@ matrix:
     - sudo: required
       services:
         - docker
+      env:
+        - RELEASE=trusty
       name: trusty
       php: '5.6'
     - sudo: required
       dist: precise
       group: edge
+      env:
+        - RELEASE=precise
       name: precise
       php: '5.6'
     - sudo: required
       arch: ppc64le
       dist: xenial
       group: edge
       language: minimal
+      env:
+        - RELEASE=xenial
       name: xenial-ppc64le
       before_install:
         - sudo rm -rf /var/lib/apt/lists/lock /var/cache/apt/archives/lock /var/lib/dpkg/lock