[ec2] better behaved volume models in relation to servers and attach/…

…detach

lib/fog/aws/models/ec2/volume.rb

@@ -20,6 +20,8 @@ class Volume < Fog::Model
         attribute :state,             'status'
 
         def initialize(attributes = {})
+          # assign server first to prevent race condition with new_record?
+          self.server = attributes.delete(:server)
           if attributes['attachmentSet']
             attributes.merge!(attributes.delete('attachmentSet').first || {})
           end
@@ -33,6 +35,10 @@ def destroy
           true
         end
 
+        def ready?
+          state == 'available'
+        end
+
         def server=(new_server)
           if new_server
             attach(new_server)
@@ -70,6 +76,7 @@ def attach(new_server)
             @server = nil
             @server_id = new_server.id
             connection.attach_volume(@server_id, @id, @device)
+            reload
           end
         end
 
@@ -78,6 +85,7 @@ def detach
           @server_id = nil
           unless new_record?
             connection.detach_volume(@id)
+            reload
           end
         end