Auto-retry `bundle install` when Travis runs tests

`bundle install` doesn't always work -- sometimes it runs into errors
making HTTP requests, for whatever reason. This will cause Travis to
fail which is pretty annoying.

* Travis supplies an executable called `travis_retry` which will
  automatically retry the command up to 3 times before really failing.
  Tell Travis to use this when it runs `bundle install` before it
  runs tests.
* In spec_helper, we create a Rails app and use this within the
  test suite. This will also run `bundle install`. Unfortunately we
  can't use `travis_retry` for this as it's a function and is not
  available to us in Ruby-land, so use our own retry logic.

.travis.yml

@@ -1,7 +1,6 @@
 script: "bundle exec rake spec cucumber"
 
-install:
-  "bundle install"
+install: "travis_retry bundle install"
 
 rvm:
   - 1.9.2

spec/spec_helper.rb

@@ -1,10 +1,34 @@
 # Create Rails environment based on the version given from Appraisal
 TESTAPP_ROOT = File.join(File.dirname(__FILE__), '..', 'tmp', 'aruba', 'testapp')
-FileUtils.rm_rf(TESTAPP_ROOT) if File.exists?(TESTAPP_ROOT)
-`rails new #{TESTAPP_ROOT}`
 
-ENV['RAILS_ENV'] = 'test'
+FileUtils.rm_rf(TESTAPP_ROOT) if File.exists?(TESTAPP_ROOT)
+
+`rails new #{TESTAPP_ROOT} --skip-bundle`
+
+ENV['RUBYOPT'] = ""
+
+Dir.chdir(TESTAPP_ROOT) do
+  retry_count = 0
+  loop do
+    puts "Current directory: #{Dir.pwd}"
+    %w(RUBYOPT BUNDLE_PATH BUNDLE_BIN_PATH BUNDLE_GEMFILE).each do |key|
+      puts "#{key}: #{ENV[key].inspect}"
+    end
+    command = 'bundle install'
+    output = Bundler.with_clean_env { `#{command} 2>&1` }
+    if $? == 0
+      break
+    else
+      retry_count += 1
+      if retry_count == 3
+        raise "Command '#{command}' failed:\n#{output}"
+      end
+    end
+  end
+end
+
 ENV['BUNDLE_GEMFILE'] ||= TESTAPP_ROOT + '/Gemfile'
+ENV['RAILS_ENV'] = 'test'
 
 require "#{TESTAPP_ROOT}/config/environment"
 require 'bourne'