[NTOS:IO]

[NTOS:IO]
- Don't delete the device node for root enumerated device objects on failure. It's pointless, since IopEnumerateDevice will just recreate it, and more importantly it causes a use-after-free because IopFreeDeviceNode does not unset the DeviceNode member of the device object extension, so IopEnumerateDevice will try to access the freed node
- Set the device object's DeviceNode pointer to NULL in IopFreeDeviceNode
- Use consistent pool tagging for device nodes
CORE-8671 #resolve

svn path=/trunk/; revision=64950