Fix bug reported by Jason@weatherserver.net - don't crash in htpasswd auth

if the auth file doesn't exist.

svn path=/icecast/trunk/icecast/; revision=9867

src/auth_htpasswd.c

@@ -129,8 +129,16 @@ static void htpasswd_recheckfile (htpasswd_auth_state *htpasswd)
     if (stat (htpasswd->filename, &file_stat) < 0)
     {
         WARN1 ("failed to check status of %s", htpasswd->filename);
+
+        /* Create a dummy users tree for things to use later */
+        thread_rwlock_wlock (&htpasswd->file_rwlock);
+        if(!htpasswd->users)
+            htpasswd->users = avl_tree_new(compare_users, NULL);
+        thread_rwlock_unlock (&htpasswd->file_rwlock);
+
         return;
     }
+
     if (file_stat.st_mtime == htpasswd->mtime)
     {
         /* common case, no update to file */