For a while gcc has been whining about a use of uninitialized.

/usr/src/usr.sbin/rpki-client/filemode.c: In function 'proc_filemode':
/usr/src/usr.sbin/rpki-client/filemode.c:316:14: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  316 |         if (a->cert->mft != NULL)
      |             ~^~~~~~
/usr/src/usr.sbin/rpki-client/filemode.c:355:22: note: 'a' was declared here
  355 |         struct auth *a;
      |                      ^

While this is a false positive, this code is tricky enough that this is
not entirely obvious. Add initialization and corresponding NULL checks.

Also switch order of aia and status since claudio mentioned he'd prefer
that.

Index: filemode.c
===================================================================
RCS file: /cvs/src/usr.sbin/rpki-client/filemode.c,v
diff -u -p -r1.47 filemode.c
--- filemode.c	17 Jun 2024 18:54:36 -0000	1.47
+++ filemode.c	16 Jul 2024 10:30:45 -0000
@@ -313,7 +313,7 @@ print_signature_path(const char *crl, co
 {
 	if (crl != NULL)
 		printf("Signature path:           %s\n", crl);
-	if (a->cert->mft != NULL)
+	if (a != NULL && a->cert != NULL && a->cert->mft != NULL)
 		printf("                          %s\n", a->cert->mft);
 	if (aia != NULL)
 		printf("                          %s\n", aia);
@@ -352,7 +352,7 @@ proc_parser_file(char *file, unsigned ch
 	char *aia = NULL;
 	char *crl_uri = NULL;
 	time_t *expires = NULL, *notafter = NULL;
-	struct auth *a;
+	struct auth *a = NULL;
 	struct crl *c;
 	const char *errstr = NULL, *valid;
 	int status = 0;
@@ -612,7 +612,7 @@ proc_parser_file(char *file, unsigned ch
 	else {
 		printf("\n");
 
-		if (status && aia != NULL) {
+		if (aia != NULL && status) {
 			print_signature_path(crl_uri, aia, a);
 			if (expires != NULL)
 				printf("Signature path expires:   %s\n",