bgpd: resolve memory leaks in "show ip bgp neighbor json"

bgpd: resolve memory leaks in "show ip bgp neighbor json"

Found several leaks in bgp_show_peer and bgp_show_peer_afi where
json objects are created and then not attached to the parent, causing
them to be leaked.  If not attaching them, freeing the created objects.
Manual testing performed successfully. Fix  tested succesfully by the
submitter and bgp-smoke completed with same failures as base.

Ticket: CM-12846
Signed-off-by: Don Slice
Reviewed-by: CCR-5181