Return valid value when falling back to openDemux am: 7633bf9e am: 9ab8a3d3 am: a70dcb93

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/23149633



Change-Id: Idccd76aebd9dc7c39845982ddacdf34920483c4a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>