Change minimum Ruby version for Puma to 2.2 + specify rdoc version under 2.2 (#2013)

Puma now requires Ruby 2.2 minimum

See: https://github.com/puma/puma/pull/1506/files

Also specify bundler version because of: rubygems/bundler#6629
Specific version should be removed when the issue is fixed on next release of bundler.

Author: benoittgt

.travis.yml

@@ -24,7 +24,7 @@ bundler_args: "--binstubs --path ../bundle --retry=3 --jobs=3"
 
 before_install:
   - gem update --system
-  - gem install bundler
+  - gem install bundler -v 1.16.2
   - script/clone_all_rspec_repos
 
 before_script:

Gemfile-rails-dependencies

@@ -13,14 +13,14 @@ when /master/
   gem 'i18n', :git => 'git://github.com/svenfuchs/i18n.git', :branch => 'master'
   gem 'sprockets', :git => 'git://github.com/rails/sprockets.git', :branch => 'master'
   gem 'sprockets-rails', :git => 'git://github.com/rails/sprockets-rails.git', :branch => 'master'
-  if RUBY_VERSION  >= "1.9.3"
+  if RUBY_VERSION  >= "2.2"
     gem 'puma', :git => 'git://github.com/puma/puma', :branch => 'master'
   end
 when /stable$/
   gem_list = %w[rails railties actionmailer actionpack activerecord activesupport]
   gem_list << 'activejob'  if version > '4-1-stable'
   gem_list << 'actionview' if version > '4-0-stable'
-  if RUBY_VERSION  >= "1.9.3"
+  if RUBY_VERSION  >= "2.2"
     gem_list << 'puma' if version > '5-0-stable'
   end
 
@@ -40,7 +40,7 @@ when nil, false, ""
 else
   gem "rails", version
 
-  if version >= '5-1-stable' && RUBY_VERSION  >= "1.9.3"
+  if version >= '5-1-stable' && RUBY_VERSION  >= "2.2"
     gem "puma"
   end
 end