account->person adaption is slow

allenap:
    person_from_account adapter seems to be having a punishing effect on
    performance

jamesh:
    The adapter should have been fairly cheap. [It was] changed it to do a
    query every time. A quick improvement would be to change the
    IAuthorization.checkAccountAuthenticated() to take both the account and
    person objects (person may be None) that would get rid of the need for
    account->person adaption in the security adapters entirely.

jamesh:
    Since the LaunchpadPrincipal has already looked up the person, feeding
    it directly to the IAuthorization adapter will probably still be faster.
    I'd expect that the majority of the calls are coming from the security
    adapter code

allenap:
    checkAccountAuthenticated in security.py which has solved my problem.
    But making person_from_team faster would be a more general fix.