Merge pull request #5750 from qlyoung/fix-null-after-xfree

*: don't null after XFREE; XFREE does this itself

diff --cc bgpd/bgp_open.c
Simple merge

diff --cc bgpd/bgp_route.c
Simple merge

diff --cc bgpd/bgp_zebra.c
Simple merge

diff --cc bgpd/bgpd.c
Simple merge

diff --cc lib/log.c
Simple merge

diff --cc zebra/zebra_nhg.c
Simple merge