tools: Utilze SENSITIVE_KEYS to prevent logging of notifier's MAIL_PASSWORD

Change-Id: Ic15eccae95c7d30667a9fefe0c6a43188887ad99
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1020871
Signed-off-by: Mooli Tayer <mtayer@redhat.com>