.travis.yml in vagrant-hosts-2.8.0 vs .travis.yml in vagrant-hosts-2.8.1

@@ -1,9 +1,15 @@
 ---
 language: ruby
 sudo: false
 before_install:
+  # TODO: Remove along with all BUNDLER_VERSION hackery once support for
+  # Vagrant < 1.9 is dropped.
+  #
+  # Travis has taken to installing Bundler as a "default" gem which locks
+  # it down and makes it extremely frustrating to use a different version.
+  - "find /home/travis/.rvm/rubies -wholename '*default/bundler-*.gemspec' -delete"
   - gem install bundler --version $BUNDLER_VERSION
 install: bundle _${BUNDLER_VERSION}_ install --without development
 script: bundle _${BUNDLER_VERSION}_ exec rspec --color --format documentation
 notifications:
   email: false
@@ -13,14 +19,14 @@
     - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
 
 matrix:
   include:
     - rvm: 2.0.0
-      env: TEST_VAGRANT_VERSION=v1.6.5 BUNDLER_VERSION=1.6.9
-    - rvm: 2.0.0
       env: TEST_VAGRANT_VERSION=v1.7.4 BUNDLER_VERSION=1.10.5
-
-    - rvm: 2.2.3
-      env: TEST_VAGRANT_VERSION=v1.8.1 BUNDLER_VERSION=1.10.6
-    - rvm: 2.2.3
-      env: TEST_VAGRANT_VERSION=HEAD BUNDLER_VERSION=1.10.6
-
+    - rvm: 2.2.5
+      env: TEST_VAGRANT_VERSION=v1.8.7 BUNDLER_VERSION=1.12.5
+    - rvm: 2.3.4
+      env: TEST_VAGRANT_VERSION=v1.9.8 BUNDLER_VERSION=1.16.1
+    - rvm: 2.4.4
+      env: TEST_VAGRANT_VERSION=v2.0.4 BUNDLER_VERSION=1.16.1
+    - rvm: 2.4.4
+      env: TEST_VAGRANT_VERSION=HEAD BUNDLER_VERSION=1.16.1