Add a delete_snapshot request method, a corresponding mock, and add support for it in the block storage provider.

lib/fog/hp/block_storage.rb

@@ -19,6 +19,7 @@ module Fog
       request :list_volumes
 
       request :create_snapshot
+      request :delete_snapshot
       request :list_snapshots
       request :get_snapshot_details
 

lib/fog/hp/requests/block_storage/delete_snapshot.rb

@@ -0,0 +1,38 @@
+module Fog
+  module BlockStorage
+    class HP
+      class Real
+
+        # Delete an existing block storage snapshot
+        #
+        # ==== Parameters
+        # * snapshot_id<~Integer> - Id of the snapshot to delete
+        #
+        def delete_snapshot(snapshot_id)
+          response = request(
+            :expects  => 202,
+            :method   => 'DELETE',
+            :path     => "os-snapshots/#{snapshot_id}"
+          )
+          response
+        end
+
+      end
+
+      class Mock # :nodoc:all
+
+        def delete_snapshot(snapshot_id)
+          response = Excon::Response.new
+          if self.data[:snapshots][snapshot_id]
+            self.data[:snapshots].delete(snapshot_id)
+            response.status = 202
+          else
+            raise Fog::BlockStorage::HP::NotFound
+          end
+          response
+        end
+      end
+
+    end
+  end
+end