Fix drop index interface

Signed-off-by: dragondriver <jiquan.long@zilliz.com>

internal/distributed/indexservice/service.go

@@ -32,6 +32,10 @@ type Server struct {
 	loopWg     sync.WaitGroup
 }
 
+func (s *Server) DropIndex(ctx context.Context, request *indexpb.DropIndexRequest) (*commonpb.Status, error) {
+	panic("implement me")
+}
+
 func (s *Server) Run() error {
 
 	if err := s.init(); err != nil {

internal/distributed/masterservice/server.go

@@ -27,6 +27,10 @@ type GrpcServer struct {
 	cancel context.CancelFunc
 }
 
+func (s *GrpcServer) DropIndex(ctx context.Context, request *milvuspb.DropIndexRequest) (*commonpb.Status, error) {
+	panic("implement me")
+}
+
 func NewGrpcServer(ctx context.Context, factory msgstream.Factory) (*GrpcServer, error) {
 	s := &GrpcServer{}
 	var err error

internal/distributed/proxynode/service.go

@@ -48,6 +48,10 @@ type Server struct {
 	indexServiceClient  *grpcindexserviceclient.Client
 }
 
+func (s *Server) DropIndex(ctx context.Context, request *milvuspb.DropIndexRequest) (*commonpb.Status, error) {
+	panic("implement me")
+}
+
 func NewServer(ctx context.Context, factory msgstream.Factory) (*Server, error) {
 
 	server := &Server{