allow parameter delimiter without space

There is a client that does not insert space before Mime Type parameter.
Ex. Salesforce OData client sends
`application/json;odata.metadata=full`. This commit allows Mime Type
string that does not have space before parameter.

The regex was introduced by
rails@ab38aa4

Author: Hiroshi Nakamura

actionpack/lib/action_dispatch/http/mime_type.rb

@@ -228,7 +228,7 @@ def unregister(symbol)
     MIME_NAME = "[a-zA-Z0-9][a-zA-Z0-9#{Regexp.escape('!#$&-^_.+')}]{0,126}"
     MIME_PARAMETER_KEY = "[a-zA-Z0-9][a-zA-Z0-9#{Regexp.escape('!#$&-^_.+')}]{0,126}"
     MIME_PARAMETER_VALUE = "#{Regexp.escape('"')}?[a-zA-Z0-9][a-zA-Z0-9#{Regexp.escape('!#$&-^_.+')}]{0,126}#{Regexp.escape('"')}?"
-    MIME_PARAMETER = "\s*\;\s+#{MIME_PARAMETER_KEY}(?:\=#{MIME_PARAMETER_VALUE})?"
+    MIME_PARAMETER = "\s*\;\s*#{MIME_PARAMETER_KEY}(?:\=#{MIME_PARAMETER_VALUE})?"
     MIME_REGEXP = /\A(?:\*\/\*|#{MIME_NAME}\/(?:\*|#{MIME_NAME})(?:\s*#{MIME_PARAMETER}\s*)*)\z/
 
     class InvalidMimeType < StandardError; end

actionpack/test/dispatch/mime_type_test.rb

@@ -194,6 +194,11 @@ class MimeTypeTest < ActiveSupport::TestCase
     assert_equal 'text/html; parameter=abc; parameter2="xyz"', Mime::Type.new('text/html; parameter=abc; parameter2="xyz"').to_s
   end
 
+  test "can be initialized with parameters without having space after ;" do
+    assert_equal "text/html;parameter", Mime::Type.new("text/html;parameter").to_s
+    assert_equal 'text/html;parameter=abc;parameter2="xyz"', Mime::Type.new('text/html;parameter=abc;parameter2="xyz"').to_s
+  end
+
   test "invalid mime types raise error" do
     assert_raises Mime::Type::InvalidMimeType do
       Mime::Type.new("too/many/slash")