Finally do away with NewLocAppError function. (#7498)

This cleans up the few NewLocAppError calls that crept in since the main
bulk of them were removed, and finally removes the NewLocAppError
function altogether.

app/file.go

@@ -309,8 +309,7 @@ func (a *App) DoUploadFile(now time.Time, teamId string, channelId string, userI
 	if info.IsImage() {
 		// Check dimensions before loading the whole thing into memory later on
 		if info.Width*info.Height > MaxImageSize {
-			err := model.NewLocAppError("uploadFile", "api.file.upload_file.large_image.app_error", map[string]interface{}{"Filename": filename}, "")
-			err.StatusCode = http.StatusBadRequest
+			err := model.NewAppError("uploadFile", "api.file.upload_file.large_image.app_error", map[string]interface{}{"Filename": filename}, "", http.StatusBadRequest)
 			return nil, err
 		}
 

app/post.go

@@ -114,7 +114,7 @@ func (a *App) CreatePost(post *model.Post, channel *model.Channel, triggerWebhoo
 		!post.IsSystemMessage() &&
 		channel.Name == model.DEFAULT_CHANNEL &&
 		!CheckIfRolesGrantPermission(user.GetRoles(), model.PERMISSION_MANAGE_SYSTEM.Id) {
-		return nil, model.NewLocAppError("createPost", "api.post.create_post.town_square_read_only", nil, "")
+		return nil, model.NewAppError("createPost", "api.post.create_post.town_square_read_only", nil, "", http.StatusForbidden)
 	}
 
 	// Verify the parent/child relationships are correct

app/webhook.go

@@ -522,7 +522,7 @@ func (a *App) HandleIncomingWebhook(hookId string, req *model.IncomingWebhookReq
 
 	if utils.IsLicensed() && *utils.Cfg.TeamSettings.ExperimentalTownSquareIsReadOnly &&
 		channel.Name == model.DEFAULT_CHANNEL {
-		return model.NewLocAppError("HandleIncomingWebhook", "api.post.create_post.town_square_read_only", nil, "")
+		return model.NewAppError("HandleIncomingWebhook", "api.post.create_post.town_square_read_only", nil, "", http.StatusForbidden)
 	}
 
 	if channel.Type != model.CHANNEL_OPEN && !a.HasPermissionToChannel(hook.UserId, channel.Id, model.PERMISSION_READ_CHANNEL) {