[ Merge of http://go/wvgerrit/23380 ]
The service certificate was setup correctly if specified in mediadrm
properties. If instead the service certificate was later fetched from
the license service, it would not be marked as valid. This led to an
infinite loop of service certificate fetches and processing. This
prevented the license from being fetched and playback failures.
b/34638410
Test: Verified by new service certificate unittests + Hulu playback
using fugu.
Change-Id: I2a4f8754614fccdad3c80d3e13fba0b44d177d61