Handle deleted accounts (SSO Follow up)

[josereyero]

As the related issue has been fixed, we need now to handle properly that new response, see
thegooddata/webapp#143

This should be a small change to account management: When we get from the master server the response "not found", we need to update accordingly the user account:

• Block account, log out any logged in user.
• Rename account to "Deleted user [number]"
• Delete all locally stored account information (name, mail, etc..)