When there is just one session and this one is invalid SecurityManager.checkAccess would cause the request to hang forever because the callback is omitted for each invalid session, this fixes this issue.
validSession still remains false so this does not cause issues further down.
Log when a sessionID in checkAccess is not found
Merge pull request #1689 from mluto/fix-checkAccess-omitted-cb

Fix missing callback in SecurityManager.checkAccess