update metal fixtures to be ruby 1.9 compat

Author: josh

railties/test/fixtures/metal/multiplemetals/app/metal/metal_a.rb

@@ -1,5 +1,5 @@
 class MetalA < Rails::Rack::Metal
   def self.call(env)
-    [200, { "Content-Type" => "text/html"}, "Hi"]
+    [200, { "Content-Type" => "text/html"}, ["Hi"]]
   end
 end

railties/test/fixtures/metal/multiplemetals/app/metal/metal_b.rb

@@ -1,5 +1,5 @@
 class MetalB < Rails::Rack::Metal
   def self.call(env)
-    [200, { "Content-Type" => "text/html"}, "Hi"]
+    [200, { "Content-Type" => "text/html"}, ["Hi"]]
   end
 end

railties/test/fixtures/metal/pluralmetal/app/metal/legacy_routes.rb

@@ -1,5 +1,5 @@
 class LegacyRoutes < Rails::Rack::Metal
   def self.call(env)
-    [301, { "Location" => "http://example.com/"}, nil]
+    [301, { "Location" => "http://example.com/"}, []]
   end
 end

railties/test/fixtures/metal/singlemetal/app/metal/foo_metal.rb

@@ -1,5 +1,5 @@
 class FooMetal < Rails::Rack::Metal
   def self.call(env)
-    [200, { "Content-Type" => "text/html"}, "Hi"]
+    [200, { "Content-Type" => "text/html"}, ["Hi"]]
   end
 end

railties/test/fixtures/metal/subfolders/app/metal/Folder/metal_a.rb

@@ -1,7 +1,7 @@
 module Folder
   class MetalA < Rails::Rack::Metal
     def self.call(env)
-      [200, { "Content-Type" => "text/html"}, "Hi"]
+      [200, { "Content-Type" => "text/html"}, ["Hi"]]
     end
   end
 end

railties/test/fixtures/metal/subfolders/app/metal/Folder/metal_b.rb

@@ -1,7 +1,7 @@
 module Folder
   class MetalB < Rails::Rack::Metal
     def self.call(env)
-      [200, { "Content-Type" => "text/html"}, "Hi"]
+      [200, { "Content-Type" => "text/html"}, ["Hi"]]
     end
   end
 end