I too have blockchain.info wallet for too long,,I never received any kind of these emails from them so which is obviously scam attempt by the people but I wonders how they know you email address which is used to login for the blockchain wallet?
Keep separate email for wallet purpose which needs to be anonymous and just use only for online wallets to restrict these emails.
Just a tip if you are logged into that mail into your android check for the application which has no icon and name which will be at the last of installed application which is the scammer's thing to hack your phone.