eventloop: support cancel state in asyncCall

Change-Id: I6582a04c0df46c8ad813a704751b04e9f4d7ab0d
Reviewed-on: http://gerrit.aldebaran.lan:8080/15183
Reviewed-by: mnottale <mnottale@aldebaran-robotics.com>
Tested-by: cgestes <gestes@aldebaran-robotics.com>