vm/qrexec: removed obsolete "directly:" command prefix support
vm/qrexec: removed obsolete "directly:" command prefix support

This was used for launching DispVM editor in pre-qrexec-RPC times.

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