Increase key status batching timeout
Increase key status batching timeout

We batch up key status changes in DrmEngine.  This increases the
timeout from 100ms to 500ms to address some flakiness in tests that
are being run in a project that depends on Shaka Player.

b/38426414

Change-Id: Ie6d8b14a981b2cff1c152f7571cd98ef4c382b96

brightcove/shaka-player,brightcove/shaka-player,brightcove/shaka-player