fix problem under plack

diff --git a/C4/Auth.pm b/C4/Auth.pm
index e360e10..5f8508c 100755 (executable)
--- a/C4/Auth.pm
+++ b/C4/Auth.pm
@@ -714,7 +714,7 @@ sub checkauth {
         elsif ( $lasttime < time() - $timeout ) {
             # timed logout
             $info{'timed_out'} = 1;
-            $session->delete();
+            $session->delete() if $session;
             C4::Context->_unset_userenv($sessionID);
             _session_log(sprintf "%20s from %16s logged out at %30s (inactivity).\n", $userid,$ip,(strftime "%c",localtime));
             $userid    = undef;