Android uses BIO reference counting.
This reverts commit 9bde6aeb76.
Change-Id: Ibf4a7f42477549d10829a424ea3b52f09098666c
Reviewed-on: https://boringssl-review.googlesource.com/4472
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>