TransportServerAsioPrivate: make _live atomic
TransportServerAsioPrivate: make _live atomic

Fix data race: http://pastebin.aldebaran.lan/view/10225f24

Change-Id: I62ed63453301cb743b7f6dd0f872097ba518fe88
Reviewed-on: http://gerrit.aldebaran.lan/76894
Reviewed-by: vpaleologue <cb19838a79eb484e12a6960acfbf7c16dfdb80d9@aldebaran-robotics.com>
Reviewed-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>
Tested-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>

aldebaran/libqi,aldebaran/libqi,aldebaran/libqi