Changed the note1 code used in MPC tests

Changed the note1 code used in MPC tests because 'M' was removed from the list of valid codes in 8db97f813253a367e5de4c53d6000aa9885ced8a and was therefore causing exceptions to be raised.

@ijiraq, @mtbannister If the purpose of the change in 8db97f813253a367e5de4c53d6000aa9885ced8a was to cut down on the number of codes available in the UI, it would have been better to remove them in config.json which the UI uses to present the options to the user (awkward that we now have them in 2 places...).  
After the removal in mpc.py, the user is still be able to select all the codes in the UI, but some of them will result in exceptions when the mpc.py module tries to use them.  

Furthermore, I think the mpc.py module should stick to the MPC "spec" of what valid codes are.  If we don't want to use all of them when blinking, we should remove them at the UI layer.