ospfd: Fix distance command

ospfd: Fix distance command

Reset prevoiusly configured distance command options
if user enters new (different) parameters.

Ticket:CM-19635
Testing Done:

R1(config-router)# distance ospf intra-area 45 external 45
R1# show running-config ospfd
router ospf
 distance ospf intra-area 45 external 45

R1(config-router)# distance ospf inter-area 45
R1# show running-config ospfd
router ospf
 distance ospf inter-area 45

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