tools: fix ospf area stub summary in frr-reload

tools: fix ospf area stub summary in frr-reload

OSPFv2 no area x stub no-summary only resets
'no-summary' config. From frr-reload if the config
line 'area x stub no-summary' is removed then
it needs to remove completely. Before this change
it took two frr-roload to remove the config which is
inconsistent behavior.
Fix is to frr-reload to add extra line to delete
'no area x stub'.

Ticket:#3514775
Testing Done:

Running config:

router ospf
 ospf router-id 6.6.6.6
 area 0.0.0.1 stub no-summary
 area 0.0.0.2 stub
exit
!
router ospf vrf sym_1
 area 0.0.1.1 range 24.1.1.0/24
 area 0.0.1.2 stub no-summary
exit

changed frr.conf:
router ospf
 ospf router-id 6.6.6.6
 area 0.0.0.2 stub
exit
!
router ospf vrf sym_1
 area 0.0.1.1 range 24.1.1.0/24
exit

Lines To Delete
===============
router ospf
 no area 0.0.0.1 stub  <<<< newly added
router ospf vrf sym_1
 no area 0.0.1.2 stub  <<<< newly added
router ospf
 no area 0.0.0.1 stub no-summary
router ospf vrf sym_1
 no area 0.0.1.2 stub no-summary

After fix new running-config post reload:
i
router ospf
 ospf router-id 6.6.6.6
 area 0.0.0.2 stub
exit
!
router ospf vrf sym_1
 area 0.0.1.1 range 24.1.1.0/24
exit

Before fix running-config post 1st reload:

router ospf
 ospf router-id 6.6.6.6
 area 0.0.0.1 stub
 area 0.0.0.2 stub
exit
!
router ospf vrf sym_1
 area 0.0.1.1 range 24.1.1.0/24
 area 0.0.1.2 stub
exit

Signed-off-by: Chirag Shah <chirag@nvidia.com>