NetBpfLoad: don't log the program failure buffer if it is empty am: 9f8b17ee5b

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3250532

Change-Id: I0557d66d34267694d97d418d2b7b68bc9809b31b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>