use correct USB PID for adb and new PID for adb+ums

The previous commit assumed that the correct PID for adb+ums
was 18d1/d001. That is incorrect. That VID/PID pair is widely
used for non-composite adb function in recovery. Since there is
no "generic Android" VID/PID allocated for adb+ums, we will
"unofficially reserve" an unused one for that purpose: 18d1/d003.

Change-Id: I6ae095569186c1e854f10b803f786d8c1ae7fb93