Resolve optional Mellanox network drivers against the target image's selected kernel. Keep real mlx_en modules, fall back to mlx4_en, include available mlx5_core, and omit missing defaults without changing explicitly requested netdrivers.
RH7/Centos7 and recent versions of fedora relocate `/*bin/*` into `/usr/*bin/`. This causes
conflicts for upgrades against xCAT-genesis-scripts-* packages which expect the `/bin` a to be
a directory while `xCAT-genesis-base-*` packages provide a link. Relocating all files into `/usr`
fixes that conflict and allows a clean upgrade from all old versions.