Bug 571656 - [Robotics, ROS2] Generated push callbacks don't compile when the communication object name matches a primitive type

- Change parameter to "commobj" in generator

- Update models as necessary (change has impact on existing functions)

- Update expected test code

Change-Id: I7b041c814f3f5df50813a36d8b5c4eeee7b8beec
Signed-off-by: Ansgar Radermacher <ansgar.radermacher@cea.fr>