Trackable: Fix a race condition (sic).
Trackable: Fix a race condition (sic).

Change-Id: I68a20218ab24ccba0447aaa91556081560697274
Reviewed-on: http://gerrit.aldebaran.lan/21054
Reviewed-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>
Tested-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>

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