Removed unused proton reference in relax_disp API calculate().
There is though some problems with these tests:
F 1.93 s for Relax_disp.test_korzhnev_2005_15n_dq_data
F 2.01 s for Relax_disp.test_korzhnev_2005_1h_mq_data
F 1.93 s for Relax_disp.test_korzhnev_2005_1h_sq_data
It is unsure where these comes from.
Bug #22754 (https://gna.org/bugs/index.php?22754): The minimise.calculate() does not calculate chi2 value for clustered residues.
