ICE connection RTP timeout status fix

This change fixes bug where second call breaks after first if first ended quickly and second started right after while using turn or stun servers.

As described here:
http://dev.w3.org/2011/webrtc/editor/webrtc.html#rtciceconnectionstate-enumhttp://dev.w3.org/2011/webrtc/editor/webrtc.html#rtciceconnectionstate-enum

<<failed	The ICE Agent is finished checking all candidate pairs and failed to find a connection for at least <<one component. Connections may have been found for some components.

<<disconnected	Liveness checks have failed for one or more components. This is more aggressive than <<failed, and may trigger intermittently (and resolve itself without action) on a flaky network.

Therefore disconnected state insufficient for session terminating because not all candidates checked.

Fixes this https://github.com/versatica/JsSIP/issues/233 issue.