Bug 1918: Set org.json.version to 20131018.

Previously used value was 20080701,
but that somehow led to (one symptom of) Bug 1918.
20131018 version is more recent,
and already present in /system repository.
The correct fix would also make other projects
refer to version defined here, to avoid skew.

Change-Id: I90d285de0fc613a6708ceecdf97afa51e1102f37
Signed-off-by: Vratko Polak <vrpolak@cisco.com>