fatal error 0x000000ca after GSoC 2016 USB merge at r73605

Seemingly consistent Duplicate device instance error occurring in pnpmgr.c:2036 (r73605) in that revision, device reported being "USB\ROOTHUB". (Error also seen in recent trunk, r73801 within week prior to this report.)

This occurs in a call tree that starts from IopReinitializeBootDrivers(), which is called before IopCreateArcNames() (both in ntoskrnl\io\iomgr\iomgr.c:IoInitSystem().)

Prior to that r73605, I was (usually**) able to make it through IopCreateArcNames() (whether successfully or not is a coin toss), but after that merge I consistently get the duplicate device error before reaching IopCreateArcNames().

I have observed there are differences in calls to IoDeleteDevice() in those merges, but my explorations have thus far failed to identify those changes as a cause. (I've tried to re-implement some of the earlier approach within the newer changes, without eliminating that error.)

actual hardware booting attempt on Acer Aspire ZG5, from flash drive.

(I do have photos of log to screen showing the error and full backtrace at point of failure. IF I can extract them from the device I will try to attach them to this, but that probably won't happen soon (as I've never yet had to extract from this device and am not assured I can do so successfully with what I currently have at my disposal.))

**with vgal's delay suggested somewhere, placed in-between IopReinitializeBootDrivers and IopCreateArcNames()