audio: Detect ADHD commit id from manifests if no branch available.

Some recents dev-channel releases have been missing a stabilize
branch in ADHD git (e.g. 5619, see #711).
Also useful for canary/custom-built images.

It is still important to look for a release or stabilize branch,
as the branch may include additional patches (stable/beta).
audio: patch_cras_x86_x86_64 is not required on build >=5652

See http://crbug.com/309961 and
https://chromium.googlesource.com/chromiumos/third_party/adhd/+/aed6ee2f614bcb3b6e325828abd9780784967b3c