sci-libs/sundials: 5.1.0 version bump

sci-libs/sundials: 5.1.0 version bump

The following changes within ebuild were made:

- FORTRAN_STANDARD=90 changed to FORTRAN_STANDARD="77 90"
(with comment that "FFLAGS and FCFLAGS if set should e equal",
otherwhise the cmake configurations error takes place);
- sorted inherit items;
- cmake-utils eclass replaced by cmake eclass;
- assignment of KLU_LIBRARY cmake variable moved to use condition expression.

Signed-off-by: Sergey Torokhov <torokhov-s-a@yandex.ru>
Signed-off-by: Joonas Niilola <juippis@gentoo.org>