Fix for systemtest: test_estimate_r2eff_err_auto()
The Jacobian to estimate the errors has been changed from the direct function Jacobian, to the Jacobian of the chi2 function.
This changes the R2eff error predictions, and hence parameter fitting.
task #7822(https://gna.org/task/index.php?7822): Implement user function to estimate R2eff and associated errors for exponential curve fitting.
Authored by: tlinnet 2014-08-29
Parent: [r25421]
Child: [r25423]
