If a key query occurred before a license was received an UNKNOWN_ERROR was
returned. This now succeeds but returns no information (an empty container).
Also licenses that were already expired when received were not marked as such.
This did not cause violations in playback rules but caused an exception when
they were queried.
[ Merge of https://widevine-internal-review.googlesource.com/#/c/12300
from wv git repo ]
b/18843625
Change-Id: I6990765c15e519ddf203a2fd8f0a130306f090a6