Changes

Bug 511469 - Memory Leak in AbstractConnectionManager

* In previous changes to fix this bug we started to reuse session ids
for the same user.
* In case an id is reused, we have to restart the lastActive flag in
order to prevent over-eager session time-outs

Change-Id: I69848ebc6c39f0ab93746e8c534a01ef81020551
Signed-off-by: Johannes Faltermeier <jfaltermeier@eclipsesource.com>