Fixing input filename for hcp3t in init_dissection_afq_trk script

[Paolopost]

The input file for the "hcp3t" dataset in in the following folder
/N/dc2/projects/lifebid/code/ccaiafa/Caiafa_Pestilli_paper2015/Results/ETC_Dec2015/Single_TC/
with the following name
fe_structure_105115_STC_run01_500000_tensor__connNUM01_TRACTS.mat
while the current wrong name is
fe_structure_105115_stc_run01_500000_tensor__connNUM01_TRACTS.mat
The one report above is just an example for the pattern of file name.