missing MTrimBar

Now the code is now more defensive as in case of missing MTrimBar there
will be no NPE. 

Change-Id: Icf0dd3a1955968bfa4869aad2420da37d564963b
Signed-off-by: Simon Scholz <simon.scholz@vogella.com>
Signed-off-by: Patrik Suzzi <psuzzi@gmail.com>