session: fix crash on close
session: fix crash on close

Change-Id: I53259e39dfbdef5c6d54989602c544a7dea42d3c
Reviewed-on: http://gerrit.aldebaran.lan/44594
Reviewed-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>
Tested-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>
Tested-by: gerrit
Reviewed-by: pdaouadi <fc1eb3334d3fdad315bae23aa166bc70bd434067@aldebaran-robotics.com>
Tested-by: pdaouadi <fc1eb3334d3fdad315bae23aa166bc70bd434067@aldebaran-robotics.com>

aldebaran/libqi,vbarbaresi/libqi,aldebaran/libqi,aldebaran/libqi,bsautron/libqi