Update MediaHandler.js - Fix Chrome HOLD.

Fix the chrome hold by allowing it to fire the readySuccess() when connection state is completed, not connected (guessing this is a Chrome assignment issue?)

When i call session.hold() in Chrome, i've found that self.peerConnection.iceConnectionState is set to completed instead of connected, this is not the case in Firefox, i think this little patch should do the job as i don't have any issues in Chrome 37.0.2062.76 beta-m, Chrome Canary 38.0.2125.0 canary (64-bit) or Firefox 31.0.

There's probably a more elegant solution to this, but for now this should work.