Activate related Ruby version to install Bundler

Without this change, the Bundler installation introduced by rvm#40 and rvm#41
fails when the `rvm_rubies` list contains valid RVM aliases, like
following examples:

 - ruby-1.9.3 (→ ruby-1.9.3-p551)
 - ruby-2.0   (→ ruby-2.0.0-p643)
 - 2.1        (→ ruby-2.1.5)
 - ruby       (→ ruby-2.2.0)
 - jruby      (→ jruby-1.7.18)
 - etc.

Add more test coverage to `.travis.yml`.

.travis.yml

@@ -35,6 +35,11 @@ script:
     | grep -q 'ruby-2.1.0'
     && (echo 'Multiple rubies test: pass' && exit 0)
     || (echo 'Multiple rubies test: fail' && exit 1)
+  - >
+    ~/.rvm/gems/ruby-2.1.2@global/bin/bundle -v
+    | grep -q 'Bundler version'
+    && (echo 'Bundler setup test: pass' && exit 0)
+    || (echo 'Bundler setup test: fail' && exit 1)
   - >
     ansible-playbook $SITE_AND_INVENTORY --connection=local --extra-vars='rvm1_delete_ruby=ruby-2.1.0'
     | grep -q 'ok=1.*failed=0'

tasks/rubies.yml

@@ -25,9 +25,7 @@
         rvm1_default_ruby_version not in detect_default_ruby_version.stdout
 
 - name: Install bundler if not installed
-  shell: >
-    {{ rvm1_install_path }}/wrappers/{{ item }}/gem list
-    | if ! grep "^bundler " ; then {{ rvm1_install_path }}/wrappers/{{ item }}/gem install bundler ; fi
+  shell: bash -lc 'cd; rvm use {{ item }}; gem list | if ! grep "^bundler " ; then gem install bundler ; fi'
   args:
     creates: '{{ rvm1_install_path }}/wrappers/{{ item }}/bundler'
   with_items: rvm1_rubies

tests/test.yml

@@ -7,7 +7,7 @@
   vars:
     rvm1_rubies:
       - 'ruby-2.1.0'
-      - 'ruby-2.1.2'
+      - '2.1.2'
     rvm1_install_path: '/home/travis/.rvm'
     rvm1_install_flags: '--auto-dotfiles --user-install'