pimd: ifdown sequnce stale report entry

pimd: ifdown sequnce stale report entry

Ticket: CM-14652
Testing Done: Tested via sending IGMP report and flap port and verified pim upstream and mroute, the entry is deleted. Run pim-smoke

Even after Report received port down event, IGMP entry alawys exists in upstream, mroute, kernel.
The entry exist because it was recreated after delete due missing check if group has no more source list,
    mode is exclude, last source address was * means (*, G) so do not trigger to create entry.

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>
Reviewed-by: Donald Sharp <sharpd@cumulusnetworks.com>