use general errors package

go.mod

@@ -26,7 +26,6 @@ require (
 	github.com/skip2/go-qrcode v0.0.0-20191027152451-9434209cb086
 	github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce
 	github.com/urfave/cli v1.22.3
-	github.com/zeebo/errs v1.2.2
 	golang.org/x/crypto v0.0.0-20200311171314-f7b00557c8c4
 	golang.org/x/net v0.0.0-20200301022130-244492dfa37a
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d

server/storage.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -16,7 +17,6 @@ import (
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/s3"
 	"github.com/aws/aws-sdk-go/service/s3/s3manager"
-	"github.com/zeebo/errs"
 	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
@@ -664,5 +664,5 @@ func (s *StorjStorage) Put(token string, filename string, reader io.Reader, cont
 }
 
 func (s *StorjStorage) IsNotExist(err error) bool {
-	return errs.Is(err, uplink.ErrObjectNotFound)
+	return errors.Is(err, uplink.ErrObjectNotFound)
 }