Remove duplicate attributes
Remove duplicate attributes

Some attributes (provisioningTime, guaranteedResources, persistentStorage) were duplicated in the g6 import script.

alphagov/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,mtekel/digitalmarketplace-api,RichardKnop/digitalmarketplace-api,mtekel/digitalmarketplace-api,alphagov/digitalmarketplace-api,alphagov/digitalmarketplace-api,mtekel/digitalmarketplace-api,mtekel/digitalmarketplace-api