make this safer and fully correct, pointed out by Steve Davis

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@306864 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_voicemail.c

@@ -2925,7 +2925,7 @@ static int last_message_index(struct ast_vm_user *vmu, char *dir)
 	DIR *msgdir;
 	struct dirent *msgdirent;
 	int msgdirint;
-	char extension[3];
+	char extension[4];
 	int stopcount = 0;
 
 	/* Reading the entire directory into a file map scales better than
@@ -2937,7 +2937,7 @@ static int last_message_index(struct ast_vm_user *vmu, char *dir)
 	}
 
 	while ((msgdirent = readdir(msgdir))) {
-		if (sscanf(msgdirent->d_name, "msg%30d.%3s", &msgdirint, extension) == 2 && msgdirint < MAXMSGLIMIT && !strcmp(extension, "txt")) {
+		if (!strcmp(extension, "txt") && msgdirint < MAXMSGLIMIT && sscanf(msgdirent->d_name, "msg%10d.%3s", &msgdirint, extension) == 2) {
 			map[msgdirint] = 1;
 			stopcount++;
 			if (option_debug > 3) {