- Use anchors in .travis.yml to keep it DRY, avoid typos.

.travis.yml

@@ -8,25 +8,22 @@ services: [docker]
 env:
     - platform: openbsd60
       driver: vagrant
-    - platform: openbsd59
-      driver: vagrant
+    - &openbsd59 platform=openbsd59 driver=vagrant
     - platform: xenial
       driver: vagrant
     - platform: trusty
       driver: vagrant
-    - platform: jessie
-      driver: vagrant
-    - platform: wheezy
-      driver: vagrant
+    - &jessie platform=jessie driver=vagrant
+    - &wheezy platform=wheezy driver=vagrant
     - driver: docker
       platform: all
 matrix:
     fast_finish: True
     allow_failures:
         - python: "3.5"
-        - env: platform=openbsd59 driver=vagrant
-        - env: platform=jessie driver=vagrant
-        - env: platform=wheezy driver=vagrant
+        - env: *openbsd59
+        - env: *jessie
+        - env: *wheezy
 cache:
   - pip
   - directories: