Fix missing semi-colon from serialised cookie jar

Author: rastating

lib/wpxf/net/cookie_jar.rb

@@ -4,7 +4,7 @@ module Net
     class CookieJar < Hash
       # @return [String] a cookie string.
       def to_s
-        map { |key, value| "#{key}=#{value}" }.join('; ')
+        map { |key, value| "#{key}=#{value};" }.join(' ')
       end
 
       # Parse a cookie into the {CookieJar}.