Change GOPATH from gerrit.opencord.org to github.com/opencord

Ran `go fmt` which did some line reordering after this change

Conformed Makefile to template the imagename and use correct DOCKER_*
build variables

Change-Id: I52734e805698b305cf64eb9238b08f152f68ffd4
diff --git a/device/utils.go b/device/utils.go
index bf5bfaa..7e0eca3 100644
--- a/device/utils.go
+++ b/device/utils.go
@@ -19,7 +19,7 @@
 import (
 	"fmt"
 
-	"gerrit.opencord.org/voltha-bbsim/common/logger"
+	"github.com/opencord/voltha-bbsim/common/logger"
 	log "github.com/sirupsen/logrus"
 	"strconv"
 )