[tests] Test bundler rack installs with supported Rack version

It's confusing here to test with a non-compatible version

Author: chadlwilson

src/main/java/org/jruby/rack/DefaultRackApplicationFactory.java

@@ -367,7 +367,7 @@ public void initRuntime(final Ruby runtime) {
     /**
      * Checks and sets the required Rack version (if specified as a magic comment).
      *
-     * e.g. # rack.version: =1.3.6
+     * e.g. # rack.version: =2.2.0
      *
      * @apiNote Internal API, only visible due tests.
      *

src/spec/ruby/rack/application_spec.rb

@@ -314,7 +314,7 @@ def newRuntime()
       end
 
       it "loads specified version of rack via bundler", :lib => :stub do
-        gem_install_unless_installed 'rack', '1.3.6'
+        gem_install_unless_installed 'rack', '2.2.0'
         set_config 'jruby.runtime.env', 'false'
 
         script = "# encoding: UTF-8\n" +
@@ -324,7 +324,7 @@ def newRuntime()
         @runtime = app_factory.newRuntime
 
         file = Tempfile.new('Gemfile')
-        file << "source 'https://rubygems.org'\n gem 'rack', '1.3.6'"
+        file << "source 'https://rubygems.org'\n gem 'rack', '2.2.0'"
         file.flush
         @runtime.evalScriptlet "ENV['BUNDLE_GEMFILE'] = #{file.path.inspect}"
         @runtime.evalScriptlet "ENV['GEM_HOME'] = #{ENV['GEM_HOME'].inspect}"
@@ -334,8 +334,8 @@ def newRuntime()
         @runtime.evalScriptlet "require 'rack'"
 
         should_not_eval_as_nil "defined?(Bundler)"
-        should_eval_as_eql_to "Rack.release if defined? Rack.release", '1.3'
-        should_eval_as_eql_to "Gem.loaded_specs['rack'].version.to_s", '1.3.6'
+        should_eval_as_eql_to "Rack.release", '2.2.0'
+        should_eval_as_eql_to "Gem.loaded_specs['rack'].version.to_s", '2.2.0'
       end
 
       it "initializes the $servlet_context global variable" do

src/spec/ruby/rack/util_spec.rb

@@ -31,10 +31,10 @@
   it "reads magic comment 2" do
     code = "# encoding: UTF-8 \n" +
            "# comment\n" +
-           "# rack.version: 1.3.6 \n" +
+           "# rack.version: 2.2.0 \n" +
            "exit(0)\n'42'"
     string = IOHelpers.rubyMagicCommentValue(code, "rack.version:")
-    expect(string).to eql "1.3.6"
+    expect(string).to eql "2.2.0"
   end
 
   it "works when reading an empty/null string" do