Delete the checkin directory with the wrong context

http://aosp/1845900 creates the directory with the wrong permission
and context. And when we attempt to fix it in http://aosp/1860276, the
device would fail to boot if the device is already on the bad build.

As a temporarily fix, already delete that checkin directory in vold. And
we can revert the deletion when the droidfood daily polulation gets out
of the bad state.

Bug: 203742483
Test: Update from TP1A.211016.001 and make sure the boot doesn't fail
Change-Id: Iec74528c1fe0e5876acc601e5cd008f99852d269