[FAB-2642] Avoid overflow of seqNum in peer metastate

While gossip state transfer being initialized it check
current height of the ledger and store in peer meta state
value of height minus one, assuming that ledger is already
contains at least one block (genesis).

In this commit added a check of the ledger height value
before initializing the state provider.

Change-Id: I86b676d6aa2b4044c44d25725bb15aa90951c204
Signed-off-by: Artem Barger <[email protected]>

Author: C0rWin

gossip/state/state.go

@@ -120,6 +120,11 @@ func NewGossipStateProvider(chainID string, g gossip.Gossip, committer committer
 	_, commChan := g.Accept(remoteStateMsgFilter, true)
 
 	height, err := committer.LedgerHeight()
+	if height == 0 {
+		// Panic here since this is an indication of invalid situation which should not happen in normal
+		// code path.
+		logger.Panic("Committer height cannot be zero, ledger should include at least one block (genesis).")
+	}
 
 	if err != nil {
 		logger.Error("Could not read ledger info to obtain current ledger height due to: ", err)