core: abandon 'kernels' in VM directory
core: abandon 'kernels' in VM directory

Since we have PV Grub now (which is much more convenient), it is useless
now.

marmarek/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin