Don't audit SSH_INVALID_USER twice.

PRIVSEP(getpwnamallow()) a few lines above already did this.

diff -ur openssh/auth2.c openssh-5.8p1/auth2.c
--- openssh/auth2.c	2011-03-02 02:32:52.383773622 +0100
+++ openssh-5.8p1/auth2.c	2011-03-02 03:32:34.585110911 +0100
@@ -250,9 +250,6 @@
 		} else {
 			logit("input_userauth_request: invalid user %s", user);
 			authctxt->pw = fakepw();
-#ifdef SSH_AUDIT_EVENTS
-			PRIVSEP(audit_event(SSH_INVALID_USER));
-#endif
 		}
 #ifdef USE_PAM
 		if (options.use_pam)