[MSS] Update fragment info management
Created by: nicosang
Hi,
this PR has to avoid 412 precondition failed error. This type of error can occur when player wants to request not already available segment. Each time that tfrf box is processed, dash.js player will only add first segment of the two entries of this box. This part of the code is used to know timestamp of the next segment, for live stream use case, without reloading smooth manifest. Thus, request scheduler is better adjust.
Nico