ThreadPool: Optimize by avoiding string creation.
ThreadPool: Optimize by avoiding string creation.

Change-Id: I713f539cb5a572cec95b443af62cdfdd9da1103e
Reviewed-on: http://gerrit.aldebaran.lan:8080/13448
Reviewed-by: cgestes <ddb78fe00abb42f91254c16a0860e38eb0781789@aldebaran-robotics.com>
Reviewed-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>
Tested-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>

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