pimd: Do not display some default values as part of a show run

pimd: Do not display some default values as part of a show run

There is no need to display igmp default values for the query-interval
and the query-max-response-time-dsec

Before change:

!
interface swp4
 description swp4 -> host-212's swp1
 ip igmp
 ip igmp query-interval 125
 ip igmp query-max-response-time-dsec 100
 ip pim ssm
 link-detect
!

After change:
!
interface br1
 ip igmp
 ip pim ssm
 link-detect
!

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>