Avoid testSetKeepUpdated to be scheduling dependant

Thread listening the changing event was started after changing event launched in testSetKeepUpdated method
Adding waiting condition between the thread startup and the onChange event will permits to the listening thread to be fully started before.

Change-Id: Ib9c5842657051abc9b44d7e0a0e007a86fe9db65
Signed-off-by: Fabou <fabien.duvoux@parrot.com>
1 file changed