Removed an unnecessary frq_struct in init of target function.
frqs can just be expanded, and back_calc is cleaned afterwards with disp_struct.
Task #7807 (https://gna.org/task/index.php?7807): Speed-up of dispersion models for Clustered analysis.
Authored by: tlinnet 2014-06-13
Parent: [r23908]
Child: [r23910]
