core : Automatic logout does not always happen as per UserSessionTimeOutInterval value

After setting UserSessionTimeOutInterval value, automatic logout
does not always happen after the set period for inactivity.
It takes much longer than the time set by the
UserSessionTimeOutInterval parameter.

Change-Id: I4866a28749b0ae1313c07bdbf22779b711892026
Bug-Url: https://bugzilla.redhat.com/953614
Signed-off-by: Ravi Nori <rnori@redhat.com>