L-curve reg param do not work with a regparam search range

[HKaras]

The two L-curve based reg param selections do not work with the brent method which is the default. No error message is given and the fit result is returned at the lower bound of the regparamrange. It would be very easy for someone to think this was the optimal value when it is actually not.

Either a warning should be raised or it should default to a grid based search method. Currently, there is no easy way to enable a grid based search from the fit function