Backport: Fix lint, fmt and integration testing errors (#2553)

* Fix lint errors

* Fix fmt errors (#2544)

* Hotfix for integration testing (#2473)

* Hotfix for integration testing

models/gpg_key.go

@@ -276,11 +276,7 @@ func DeleteGPGKey(doer *User, id int64) (err error) {
 		return err
 	}
 
-	if err = sess.Commit(); err != nil {
-		return err
-	}
-
-	return nil
+	return sess.Commit()
 }
 
 // CommitVerification represents a commit validation of signature

models/issue.go

@@ -572,11 +572,7 @@ func (issue *Issue) ReadBy(userID int64) error {
 		return err
 	}
 
-	if err := setNotificationStatusReadIfUnread(x, userID, issue.ID); err != nil {
-		return err
-	}
-
-	return nil
+	return setNotificationStatusReadIfUnread(x, userID, issue.ID)
 }
 
 func updateIssueCols(e Engine, issue *Issue, cols ...string) error {

models/login_source.go

@@ -509,10 +509,7 @@ func SMTPAuth(a smtp.Auth, cfg *SMTPConfig) error {
 	}
 
 	if ok, _ := c.Extension("AUTH"); ok {
-		if err = c.Auth(a); err != nil {
-			return err
-		}
-		return nil
+		return c.Auth(a)
 	}
 	return ErrUnsupportedLoginType
 }

models/migrations/v16.go

@@ -119,9 +119,5 @@ func addUnitsToTables(x *xorm.Engine) error {
 		}
 	}
 
-	if err := sess.Commit(); err != nil {
-		return err
-	}
-
-	return nil
+	return sess.Commit()
 }

models/migrations/v21.go

@@ -51,8 +51,5 @@ func useNewPublickeyFormat(x *xorm.Engine) error {
 	}
 
 	f.Close()
-	if err = os.Rename(tmpPath, fpath); err != nil {
-		return err
-	}
-	return nil
+	return os.Rename(tmpPath, fpath)
 }

models/org.go

@@ -235,11 +235,7 @@ func DeleteOrganization(org *User) (err error) {
 		}
 	}
 
-	if err = sess.Commit(); err != nil {
-		return err
-	}
-
-	return nil
+	return sess.Commit()
 }
 
 func deleteOrg(e *xorm.Session, u *User) error {

models/ssh_key.go

@@ -609,11 +609,7 @@ func RewriteAllPublicKeys() error {
 		defer f.Close()
 	}
 
-	if err = os.Rename(tmpPath, fPath); err != nil {
-		return err
-	}
-
-	return nil
+	return os.Rename(tmpPath, fPath)
 }
 
 // ________                .__                 ____  __.