Autotest: touch_WakeupSource prevent missing file from causing a failure.

After clarification from bleung@, a missing wakeup file effectively means
that the device is incapable of being a wakeup source, e.g. some of our
touchscreens.  Since we only care about checking that the touchscreen /isn't/
a wakeup source, interpret a missing file as 'not a wakeup source'.

TEST=this; ran it on previously failing devices
BUG=None

Change-Id: I85ca38236ffd726222629a1fdc5e9c20538f0876
Reviewed-on: https://chromium-review.googlesource.com/225782
Reviewed-by: harpreet Grewal <harpreet@chromium.org>
Commit-Queue: Katherine Threlkeld <kathrelkeld@chromium.org>
Tested-by: Katherine Threlkeld <kathrelkeld@chromium.org>
1 file changed