exc: fix QubesMemoryError constructor
exc: fix QubesMemoryError constructor

QubesVMError require 'vm' argument.
Fixes 2f3a9847 "exc: Make QubesMemoryError inherit from QubesVMError"

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