bugfix - fixed regression error revealed by test_neuromag_units in magnetic_dipole due to a change in variable names in http://code.google.com/p/fieldtrip/source/detail?r=8809


git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@8814 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0