Add a head method for the directories collection.

lib/fog/hp/models/storage/directories.rb

@@ -14,6 +14,33 @@ module Fog
           load(data)
         end
 
+        def head(key, options = {})
+          read_header = nil
+          write_header = nil
+          data = connection.head_container(key)
+          directory = new(:key => key)
+          for key, value in data.headers
+            if ['X-Container-Bytes-Used', 'X-Container-Object-Count'].include?(key)
+              directory.merge_attributes(key => value)
+            end
+            if key == 'X-Container-Read'
+              read_header = value
+            elsif key == 'X-Container-Write'
+              write_header = value
+            end
+          end
+          # set the acl on the directory based on the headers
+          if !(read_header.nil? && write_header.nil?)
+            directory.acl = connection.header_to_acl(read_header, write_header)
+          end
+          # set the cdn state for the directory
+          directory.cdn_enabled?
+
+          directory
+        rescue Fog::Storage::HP::NotFound
+          nil
+        end
+
         def get(key, options = {})
           read_header = nil
           write_header = nil