ospfd: Summary LSA is not originated when process is reset

ospfd: Summary LSA is not originated when process is reset

Problem Statement:
==================
Summary LSA is not originated when router-id is modified or process is reset

Root Cause Analysis:
====================
When router-id is modified or process is cleared, all the external LSAs are
 flushed then LSA is re-originated using ospf_external_lsa_rid_change
When the LSAs are flushed, the aggregate flags are not reset.

Fix:
===============
Reset the aggregation flag when the LSAs
 are flushed.

Signed-off-by: Mobashshera Rasool <mrasool@vmware.com>