Upgrade to version 2.1 of license protocol in OEMCrypto.
related-to-bug: 8621521
Merge of https://widevine-internal-review.googlesource.com/#/c/4952/
from Widevine CDM repository to android repository.
Change-Id: I0d85dae1981b7525ab17aec5f21cf668d078bf47