vm/qubesvm: forbid '/' in kernel property
vm/qubesvm: forbid '/' in kernel property

It would give VM access to some files outside of
/var/lib/qubes/vm-kernels.

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