[FAB-4475] Sync gossip ledger height & metastate

The state transfer asks the ledger what is its ledger height, but
compares the height to the maximum block number of the peers of the channel
which is always 1 behind the ledger height, since block sequence of 0
means ledger height of 1.

Change-Id: If7ff1ad56ae765c8cdadf9b9725dc18a05b49691
Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>

gossip/state/state.go

@@ -460,9 +460,13 @@ func (s *GossipStateProviderImpl) antiEntropy() {
 				logger.Error("Cannot obtain ledger height, due to", err)
 				continue
 			}
+			if current == 0 {
+				logger.Error("Ledger reported block height of 0 but this should be impossible")
+				continue
+			}
 			max := s.maxAvailableLedgerHeight()
 
-			if current == max {
+			if current-1 >= max {
 				continue
 			}