ZwSetValueKey() was being called at DISPATCH_LEVEL from within the enumeration code.
ZwSetValueKey() was being called at DISPATCH_LEVEL from within the
enumeration code.

Change the code structure to only play with the registry from the outer
scan function which runs at PASSIVE_LEVEL.

Signed-off-by: Paul Durrant <dba6cd059c0054f8a3c62ba902cd9d7238853ee4@citrix.com>

xenserver/win-xenvbd,xenserver/win-xenvbd,xenserver/win-xenvbd