It would be useful to include the database name in auth log messages.

For example, if we have a user "someuser" in the database "somedb", the log message would currently read (2.0.3-rc1):

authenticate:

{ authenticate: 1, nonce: "abcd1234", user: "someuser", key: "abcd1234abcd1234" }

That might become:

authenticate:

{ authenticate: 1, nonce: "abcd1234", db: "somedb", user: "someuser", key: "abcd1234abcd1234" }

or maybe:

authenticate:

{ authenticate: 1, nonce: "abcd1234", user: "somedb.someuser", key: "abcd1234abcd1234" }