AbstractUserDetailsAuthenticationProvider should lazily compose debug message

[jzheaux]

AbstractUserDetailsAuthenticationProvider logs the following:

this.logger.debug("Failed to find user '" + username + "'")

This could be improved by not composing the message regardless of logging level. LogMessage is a nice utility for this;

this.logger.debug(LogMessage.format("Failed to find user '%s'", username));

This makes so that the message is only concatenated if the logging level is DEBUG or higher.