tree cbeb473b92ce0eeb200f631ee618a616501446df
parent 4a098bbe213e8640cd80941145cf0eb6ca39a869
author Dan Albert <danalbert@google.com> 1430956132 -0700
committer Dan Albert <danalbert@google.com> 1430956132 -0700

Be tolerant of devices that don't report serials.

The USB spec explicitly says this is optional, so we shouldn't be
relying on it.

Bug: http://b/20883914
Change-Id: Icf38405b00275199bcf51a70c47d428ae7264f2b