Add attributes to image model by extracting them from metadata.

lib/fog/hp/models/compute/image.rb

@@ -14,12 +14,16 @@ module Fog
         attribute :updated_at,  :aliases => 'updated'
         attribute :progress
         attribute :status
-        attribute :minDisk,     :aliases => 'min_disk'
-        attribute :minRam,      :aliases => 'min_ram'
         attribute :server
         attribute :metadata
         attribute :links
 
+        # these values are extracted from metadata
+        attr_reader :min_disk
+        attr_reader :min_ram
+        attr_reader :image_type
+        attr_reader :architecture
+
         def initialize(attributes)
           @connection = attributes[:connection]
           super
@@ -40,6 +44,26 @@ module Fog
           metadata.load(metas)
         end
 
+        def min_disk
+          m = metadata.get("min_disk")
+          m.value unless m.nil?
+        end
+
+        def min_ram
+          m = metadata.get("min_ram")
+          m.value unless m.nil?
+        end
+
+        def image_type
+          m = metadata.get("image_type")
+          m.value unless m.nil?
+        end
+
+        def architecture
+          m = metadata.get("architecture")
+          m.value unless m.nil?
+        end
+
         def destroy
           requires :id