fix code style issues reported by golint

src/adminserver/systemcfg/store/json/driver_json.go

@@ -115,9 +115,5 @@ func (c *cfgStore) Write(config map[string]interface{}) error {
 		return err
 	}
 
-	if err = ioutil.WriteFile(c.path, b, 0600); err != nil {
+	return ioutil.WriteFile(c.path, b, 0600)
-		return err
-	}
-
-	return nil
 }

src/common/dao/repository_test.go

@@ -267,8 +267,5 @@ func deleteRepository(name string) error {
 }
 
 func clearRepositoryData() error {
-	if err := ClearTable(models.RepoTable); err != nil {
+	return ClearTable(models.RepoTable)
-		return err
-	}
-	return nil
 }

src/common/dao/sqlite.go

@@ -42,11 +42,7 @@ func (s *sqlite) Register(alias ...string) error {
 	if len(alias) != 0 {
 		an = alias[0]
 	}
-	if err := orm.RegisterDataBase(an, "sqlite3", s.file); err != nil {
+	return orm.RegisterDataBase(an, "sqlite3", s.file)
-		return err
-	}
-
-	return nil
 }
 
 // Name returns the name of SQLite

src/jobservice/job/job_test.go

@@ -15,6 +15,10 @@ package job
 
 import (
 	"fmt"
+	"os"
+	"strconv"
+	"testing"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/vmware/harbor/src/common"
 	"github.com/vmware/harbor/src/common/dao"
@@ -22,9 +26,6 @@ import (
 	"github.com/vmware/harbor/src/common/utils/log"
 	"github.com/vmware/harbor/src/common/utils/test"
 	"github.com/vmware/harbor/src/jobservice/config"
-	"os"
-	"strconv"
-	"testing"
 )
 
 var repJobID, scanJobID int64
@@ -192,10 +193,7 @@ func clearRepJobData() error {
 	if err := dao.ClearTable(models.RepPolicyTable); err != nil {
 		return err
 	}
-	if err := dao.ClearTable(models.RepTargetTable); err != nil {
+	return dao.ClearTable(models.RepTargetTable)
-		return err
-	}
-	return nil
 }
 
 func prepareScanJobData() error {
@@ -220,8 +218,5 @@ func clearScanJobData() error {
 	if err := dao.ClearTable(models.ScanJobTable); err != nil {
 		return err
 	}
-	if err := dao.ClearTable(models.ScanOverviewTable); err != nil {
+	return dao.ClearTable(models.ScanOverviewTable)
-		return err
-	}
-	return nil
 }

src/ui/api/user.go

@@ -357,10 +357,7 @@ func validate(user models.User) error {
 	if isIllegalLength(user.Password, 8, 20) {
 		return fmt.Errorf("password with illegal length")
 	}
-	if err := commonValidate(user); err != nil {
+	return commonValidate(user)
-		return err
-	}
-	return nil
 }
 
 //commonValidate validates email, realname, comment information when user register or change their profile