Fixes database error on save().
Fixes database error on save().

update_fields should not be used if the object has not been saved once.

czpython/djangocms-text-ckeditor,vxsx/djangocms-text-ckeditor,yakky/djangocms-text-ckeditor,divio/djangocms-text-ckeditor,divio/djangocms-text-ckeditor,yakky/djangocms-text-ckeditor,czpython/djangocms-text-ckeditor,czpython/djangocms-text-ckeditor,divio/djangocms-text-ckeditor,vxsx/djangocms-text-ckeditor,czpython/djangocms-text-ckeditor,divio/djangocms-text-ckeditor,vxsx/djangocms-text-ckeditor,yakky/djangocms-text-ckeditor,vxsx/djangocms-text-ckeditor