Make MediaPlayer fail fast on UnknownServiceException.

This makes MediaPlayer's network streaming code fail fast when an
UnknownServiceException is encountered. This currently occurs when the
application declares that it does not perform cleartext network
traffic and tries to load media over cleartext HTTP. Without this CL,
MediaPlayer blocks for 30 seconds because it treats this error as
recoverable and goes into a ten retry loop with a three second delay
before each retry.

The result at MediaPlayer client level is
MediaPlayer.MEDIA_ERROR_UNKNOWN error. This error code is used for
non-recoverable situations such as when an invalid redirect is
encountered or the destination is unreachable.

Bug: 20026006
Change-Id: I10f0dadb7740902f8c7c73d0df96cfff31f08ada