enable full linter across the codebase (#9620)

enable linter using golangci-lint across
codebase to run a bunch of linters together,
we shall enable new linters as we fix more
things the codebase.

This PR fixes the first stage of this
cleanup.

cmd/config/etcd/dns/types.go

@@ -23,7 +23,6 @@ import (
 
 const (
 	defaultTTL            = 30
-	defaultPrefixPath     = "/skydns"
 	defaultContextTimeout = 5 * time.Minute
 )
 

cmd/config/identity/openid/ecdsa-sha3.go

@@ -18,7 +18,9 @@ package openid
 
 import (
 	"crypto"
+
 	"github.com/dgrijalva/jwt-go"
+
 	// Needed for SHA3 to work - See: https://golang.org/src/crypto/crypto.go?s=1034:1288
 	_ "golang.org/x/crypto/sha3"
 )

cmd/config/identity/openid/jwt.go

@@ -30,7 +30,7 @@ import (
 	"github.com/minio/minio/cmd/config"
 	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/env"
-	"github.com/minio/minio/pkg/iam/policy"
+	iampolicy "github.com/minio/minio/pkg/iam/policy"
 	xnet "github.com/minio/minio/pkg/net"
 )
 

cmd/config/identity/openid/rsa-sha3.go

@@ -18,7 +18,9 @@ package openid
 
 import (
 	"crypto"
+
 	"github.com/dgrijalva/jwt-go"
+
 	// Needed for SHA3 to work - See: https://golang.org/src/crypto/crypto.go?s=1034:1288
 	_ "golang.org/x/crypto/sha3"
 )

cmd/config/notify/parse.go

@@ -36,7 +36,6 @@ import (
 
 const (
 	formatNamespace = "namespace"
-	formatAccess    = "access"
 )
 
 // ErrTargetsOffline - Indicates single/multiple target failures.