periodictask: handle stopping state in start
periodictask: handle stopping state in start

Change-Id: I8aeaacfad2cf5aff1b2c02b60c0c47e01a9e2469
Reviewed-on: http://gerrit.aldebaran.lan/34494
Reviewed-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>
Tested-by: cgestes <ddb78fe00abb42f91254c16a0860e38eb0781789@aldebaran-robotics.com>

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