This change allows the security level, after it is forced from L1 to L3, to be reset back to L1 using the string "L1" instead of only allowing the reset string. (the empty string) Merge of https://widevine-internal-review.googlesource.com/#/c/8928/ from the widevine cdm repo. Bug: 10651521 Change-Id: I39797bb0a51b82db3543aec800a08ad36e11d661