* Handle AuthenticationFailedException separately:
This exception is a subclass of AccountException that is thrown if the
user provides wrong credentials. For this exception we want to return
"Invalid username or password." as message to the client.
* Return a more general message for other AccountExceptions:
Likely they are not caused by invalid username or password since this
would cause a AuthenticationFailedException which we handle before.
* Increase log level to warning:
This is the log level that we use for these exceptions in other places
(e.g. ProjectBasicAuthFilter). Make it consistent.
* Log the stacktrace for AccountExceptions:
We do this everywhere else (e.g. ProjectBasicAuthFilter,
HttpLoginServlet). Make it consistent.
Change-Id: Ie34687d087b5a6cd102bf8cebd0f9830f54c9c1c
Signed-off-by: Edwin Kempin <ekempin@google.com>