SEBA-663 VOLTHA 1.7 support in BBSim
Error handling in FlowRemove()
Error handling in getGemPortId
Update README for supporting VOLTHA 1.7

Change-Id: Ib9e76282f8bdf2b7b66bbf745521bca31cd4a219
diff --git a/core/core_server.go b/core/core_server.go
index 2033ec1..17404e3 100644
--- a/core/core_server.go
+++ b/core/core_server.go
@@ -19,10 +19,11 @@
 import (
 	"context"
 	"errors"
-	"reflect"
 	"strconv"
 	"sync"
+	"reflect"
 
+	omci "github.com/opencord/omci-sim"
 	"gerrit.opencord.org/voltha-bbsim/common/logger"
 	"gerrit.opencord.org/voltha-bbsim/common/utils"
 	"gerrit.opencord.org/voltha-bbsim/device"
@@ -30,7 +31,6 @@
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/google/gopacket/pcap"
-	omci "github.com/opencord/omci-sim"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
 	"google.golang.org/grpc"