Allow specifying redundant default port in origin

When `http://EXAMPLE:80` is an allowed origin, requests are not allowed from
`http://EXAMPLE`. Since port 80 is the default port for HTTP, browsers
will strip it and thus rack-cors never receives a request from `http://EXAMPLE`.

A similar problem is discussed here: request/request#515

lib/rack/cors.rb

@@ -278,8 +278,8 @@ def origins(*args, &blk)
             case n
             when Proc,
                  Regexp,
-                 /^https?:\/\//,
                  'file://'        then n
+            when  /^https?:\/\//  then URI.parse(n).to_s
             when '*'              then @public_resources = true; n
             else                  Regexp.compile("^[a-z][a-z0-9.+-]*:\\\/\\\/#{Regexp.quote(n)}$")
             end

test/unit/cors_test.rb

@@ -270,6 +270,13 @@ def load_app(name)
       cors_result.must_be :preflight
     end
 
+    it 'should allow HTTP/HTTPS origin without the default port' do
+      preflight_request('http://allow-the-default-port.io', '/')
+      last_response.must_render_cors_success
+      preflight_request('https://allow-the-default-port.io', '/')
+      last_response.must_render_cors_success
+    end
+
     it 'should allow any header if headers = :any' do
       preflight_request('http://localhost:3000', '/', :headers => 'Fooey')
       last_response.must_render_cors_success

test/unit/test.ru

@@ -8,7 +8,9 @@ use Rack::Cors do
             '127.0.0.1:3000',
             /http:\/\/192\.168\.0\.\d{1,3}(:\d+)?/,
             'file://',
-            /http:\/\/(.*?)\.example\.com/
+            /http:\/\/(.*?)\.example\.com/,
+            'http://allow-the-default-port.io:80',
+            'https://allow-the-default-port.io:443'
 
     resource '/get-only', :methods => :get
     resource '/', :headers => :any, :methods => :any