Go one directory up looking for releasetools path

Change I366099c3dfd5fa4282745ef258a8cf35338e1e42 introduced a more
restricted search where we only look in out/host/x/bin instead of
out/host/x when looking for files.

Because signapk is in out/host/x/framework, and lib64 is in out/host/x,
we need to go one level up for this to work properly.

Fix: 147096688
Test: atest --host releasetools_test releasetools_py3_test
Change-Id: I597e1d95c09eb0e27b2faebb107218761901d9ac