upstream: return SSH_ERR_KEY_NOT_FOUND if the allowed_signers file

is empty, not SSH_ERR_INTERNAL_ERROR. Also remove some dead code spotted
by Coverity; with/ok dtucker@

OpenBSD-Commit-ID: 898a1e817cda9869554b1f586a434f67bcc3b650

sshsig.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: sshsig.c,v 1.30 2022/08/19 03:06:30 djm Exp $ */
+/* $OpenBSD: sshsig.c,v 1.31 2023/03/30 03:05:01 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -977,7 +977,7 @@ sshsig_check_allowed_keys(const char *path, const struct sshkey *sign_key,
 	char *line = NULL;
 	size_t linesize = 0;
 	u_long linenum = 0;
-	int r = SSH_ERR_INTERNAL_ERROR, oerrno;
+	int r = SSH_ERR_KEY_NOT_FOUND, oerrno;
 
 	/* Check key and principal against file */
 	if ((f = fopen(path, "r")) == NULL) {
@@ -1007,7 +1007,7 @@ sshsig_check_allowed_keys(const char *path, const struct sshkey *sign_key,
 	/* Either we hit an error parsing or we simply didn't find the key */
 	fclose(f);
 	free(line);
-	return r == 0 ? SSH_ERR_KEY_NOT_FOUND : r;
+	return r;
 }
 
 int