Fix the maven build problem caused by incorrect protobuf model

Change-Id: Ifda88b64710802ad3291362a8618969f4c63ed83
diff --git a/incubator/rpc-grpc/src/main/proto/DeviceService.proto b/incubator/rpc-grpc/src/main/proto/DeviceService.proto
index 9ff86c5..023af13 100644
--- a/incubator/rpc-grpc/src/main/proto/DeviceService.proto
+++ b/incubator/rpc-grpc/src/main/proto/DeviceService.proto
@@ -4,7 +4,7 @@
 import "net/device/DeviceDescriptionProto.proto";
 import "net/device/PortDescriptionProto.proto";
 import "net/device/PortStatisticsProto.proto";
-import "net/device/DeviceEnumsProto.proto";
+import "net/MastershipRoleProto.proto";
 
 package Device;
 
@@ -34,8 +34,8 @@
 message ReceivedRoleReply {
   // DeviceID as String DeviceId#toString
   string device_id = 1;
-  net.device.MastershipRoleProto requested = 2;
-  net.device.MastershipRoleProto response = 3;
+  net.MastershipRoleProto requested = 2;
+  net.MastershipRoleProto response = 3;
 }
 
 message UpdatePortStatistics {
@@ -74,7 +74,7 @@
 message RoleChanged {
   // DeviceID as String DeviceId#toString
   string device_id = 1;
-  net.device.MastershipRoleProto new_role = 2;
+  net.MastershipRoleProto new_role = 2;
 }
 
 message IsReachableRequest {