[#339] pool/tree: Fix linter issues

Signed-off-by: Alex Vanin <a.vanin@yadro.com>

pool/tree/circuitbreaker.go

@@ -23,7 +23,7 @@ type (
 
 var ErrCBClosed = errors.New("circuit breaker is closed")
 
-func NewCircuitBreaker(breakDuration time.Duration, threshold int) *circuitBreaker {
+func newCircuitBreaker(breakDuration time.Duration, threshold int) *circuitBreaker {
 	return &circuitBreaker{
 		breakDuration: breakDuration,
 		threshold:     threshold,

pool/tree/circuitbreaker_test.go

@@ -12,7 +12,7 @@ func TestCircuitBreaker(t *testing.T) {
 	remoteErr := errors.New("service is being synchronized")
 	breakDuration := 1 * time.Second
 	threshold := 10
-	cb := NewCircuitBreaker(breakDuration, threshold)
+	cb := newCircuitBreaker(breakDuration, threshold)
 
 	// Hit threshold
 	for i := 0; i < threshold; i++ {

pool/tree/pool.go

@@ -254,7 +254,7 @@ func NewPool(options InitParameters) (*Pool, error) {
 		methods:            methods,
 		netMapInfoSource:   options.netMapInfoSource,
 		clientMap:          make(map[uint64]client),
-		cb: NewCircuitBreaker(
+		cb: newCircuitBreaker(
 			options.circuitBreakerDuration,
 			options.circuitBreakerThreshold,
 		),
@@ -802,7 +802,6 @@ func fillDefaultInitParams(params *InitParameters) {
 
 	if params.circuitBreakerDuration <= 0 {
 		params.circuitBreakerDuration = defaultCircuitBreakerDuration
-
 	}
 
 	if params.circuitBreakerThreshold <= 0 {