Do not use two id_user/uid arguments to perform_remove_alert().  Also, print explicit error message when alerts cannot be deleted.
Do not use two id_user/uid arguments to perform_remove_alert().  Also,
print explicit error message when alerts cannot be deleted.

tiborsimko/invenio,tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio