Corrected a regression in error event reporting and a
mismatch in asset paths during rights acquisition.
Also requires https://android-git.corp.google.com/g/#/c/185898/
Contains Widevine libraries version 6.0.0-6957
Change-Id: I4a7603a86feaf437673fc73f0cccb6065dbcce67
related-to-bug: 6414503