Don't fail if vold.fstab is empty

This test shouldn't fail if vold.fstab is empty.  Rather, short
term, just ignore this case, at the expense that we may miss
legitimate security holes.

Long term, this needs to be properly fixed.

Change-Id: I328bc0360048b5233b336c1a35f7d8a9ade3c49c
1 file changed