ospfd: Display nssa in show running-config

ospfd: Display nssa in show running-config

Display area x.x.x.x nssa configuration in
running-config. Using nssa translate candiate (default)
case to display 'area x nssa'.

Ticket:CM-18947
Reviewed By:
Testing Done:
Tried various combinations of nssa config,
verified show running-config ospfd output

router ospf
 area 2.2.2.2 nssa
  area 2.2.2.2 nssa no-summary

router ospf
 area 2.2.2.2 nssa translate-always
  area 2.2.2.2 nssa no-summary

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