MFC r208018
MFC r208018

 Reduce diffs to p4.

  Add test code for delaying or failing usb control requests, disabled by
  default under ifdef USB_REQ_DEBUG.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase