[#607] *: Remove redundant if on error returns

Semantic patch:
```
@@
@@
-if err != nil { return err }
-return nil
+return err
```

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/innerring/initialization.go

@@ -246,11 +246,7 @@ func (s *Server) initAlphabetProcessor(cfg *viper.Viper) error {
 	}
 
 	err = bindMorphProcessor(s.alphabetProcessor, s)
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }
 
 func (s *Server) initContainerProcessor(cfg *viper.Viper, cnrClient *container.Client,
@@ -454,11 +450,7 @@ func (s *Server) initProcessors(cfg *viper.Viper, morphClients *serverMorphClien
 	}
 
 	err = s.initAlphabetProcessor(cfg)
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }
 
 func (s *Server) initMorph(ctx context.Context, cfg *viper.Viper, errChan chan<- error) (*chainParams, error) {

pkg/local_object_storage/blobstor/compression/compress.go

@@ -33,11 +33,7 @@ func (c *Config) Init() error {
 	}
 
 	c.decoder, err = zstd.NewReader(nil)
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }
 
 // NeedsCompression returns true if the object should be compressed.

pkg/local_object_storage/pilorama/boltdb.go

@@ -146,10 +146,7 @@ func (t *boltForest) Init() error {
 			return err
 		}
 		_, err = tx.CreateBucketIfNotExists(logBucket)
-		if err != nil {
+		return err
-			return err
-		}
-		return nil
 	})
 }
 func (t *boltForest) Close() error {

pkg/morph/client/notifications.go

@@ -101,9 +101,5 @@ func (c *Client) UnsubscribeAll() error {
 	}
 
 	err := c.client.UnsubscribeAll()
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }

pkg/morph/event/notary_preparator.go

@@ -243,11 +243,7 @@ func (p Preparator) validateParameterOpcodes(ops []Op) error {
 	}
 
 	err = validateNestedArgs(argsLen, ops[:l-2])
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }
 
 func validateNestedArgs(expArgLen int64, ops []Op) error {

pkg/services/notificator/nats/service.go

@@ -74,11 +74,7 @@ func (n *Writer) Notify(topic string, address oid.Address) error {
 	}
 
 	_, err := n.js.Publish(topic, []byte(address.EncodeToString()), nats.MsgId(messageID))
-	if err != nil {
+	return err
-		return err
-	}
-
-	return nil
 }
 
 // New creates new Writer.

pkg/services/session/storage/persistent/storage.go

@@ -102,11 +102,7 @@ func (s *TokenStore) Get(ownerID user.ID, tokenID []byte) (t *storage.PrivateTok
 		var err error
 
 		t, err = s.unpackToken(rawToken)
-		if err != nil {
+		return err
-			return err
-		}
-
-		return nil
 	})
 	if err != nil {
 		s.l.Error(logs.PersistentCouldNotGetSessionFromPersistentStorage,