Revert work arounds for upstream Ruby 2.2.0 kwargs bug

The bug caused a segfault and you can find more info about it at:
https://bugs.ruby-lang.org/issues/10685.

We did a couple of work arounds, but 2.2.1 rolled out and those aren't
needed anymore.

Here are the reverted commits:

- Revert "Work around for upstream Ruby bug #10685",
  commit 707a433870e9e06af688f85a4aedc64a90791a64.

- Revert "Fix segmentation fault in ActionPack tests",
  commit 22e0a22d5f98e162290d9820891d8191e720ad3b.

I'm also bumping the Ruby version check to 2.2.1 to prevent future
segfaults.

2 files changed, 2 insertions, 4 deletions

diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 5fe544c60c..a895d1ab18 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -113,9 +113,7 @@ module ActionDispatch # :nodoc:
     # The underlying body, as a streamable object.
     attr_reader :stream
 
-    # Ruby 2.2 bug https://bugs.ruby-lang.org/issues/10685 prevents
-    # default_headers from being a keyword argument.
-    def initialize(status = 200, header = {}, body = [], default_headers = self.class.default_headers)
+    def initialize(status = 200, header = {}, body = [], default_headers: self.class.default_headers)
       super()
 
       header = merge_default_headers(header, default_headers)
diff --git a/actionpack/lib/action_dispatch/testing/test_response.rb b/actionpack/lib/action_dispatch/testing/test_response.rb
index 527784885c..a9b88ac5fd 100644
--- a/actionpack/lib/action_dispatch/testing/test_response.rb
+++ b/actionpack/lib/action_dispatch/testing/test_response.rb
@@ -7,7 +7,7 @@ module ActionDispatch
   # See Response for more information on controller response objects.
   class TestResponse < Response
     def self.from_response(response)
-      new response.status, response.headers, response.body, nil
+      new response.status, response.headers, response.body, default_headers: nil
     end
 
     # Was the response successful?