ENH: fix memory management of generic kernel in the svm_parameter struct

Code/Learning/otbChangeProfileKernelFunctor.h

Code/Learning/otbMixturePolyRBFKernelFunctor.h

Code/Learning/otbNonGaussianRBFKernelFunctor.h

Code/Learning/otbSVMKernels.h

Code/Learning/otbSVMModel.h

Code/Learning/otbSVMModel.txx

Code/Learning/otbSpectralAngleKernelFunctor.h

Utilities/otbsvm/svm.cpp

Utilities/otbsvm/svm.h