Merge branch 'remove_thumbnail' into 'master'

Implemented thumbnail removal

See merge request portalmec/portalmec!493

app/controllers/v1/learning_objects_controller.rb

@@ -74,10 +74,17 @@ class V1::LearningObjectsController < ApplicationController
   # PATCH/PUT /learning_objects/1
   # PATCH/PUT /learning_objects/1.json
   def update
-    if !learning_object_params[:object_type_id].blank? && learning_object_params[:object_type_id] != @learning_object.object_type_id && learning_object_params[:link].blank?
+    lo_params = learning_object_params
+    if !lo_params[:object_type_id].blank? && lo_params[:object_type_id] != @learning_object.object_type_id && lo_params[:link].blank?
       change_object_type_id = true
     end
-    if @learning_object.update(learning_object_params)
+
+    if lo_params[:thumbnail] == "null"
+      @learning_object.thumbnail.clear
+      lo_params.delete(:thumbnail)
+    end
+
+    if @learning_object.update(lo_params)
       update_learning_object_associations(@learning_object, change_object_type_id)
       publisher = LearningObjectPublisher.new(DspaceService.create_client)
       publisher.update_dspace(@learning_object)