Fixes an issue reported by @klauspost and @vadmeste
This PR also allows users to expand their clusters
from single node XL deployment to distributed mode.
This is an effort to remove panic from the source.
Add a new call called CriticialIf, that calls LogIf and exits.
Replace panics with one of CriticalIf, FatalIf and a return of error.
Harshavardhana