Merge pull request #5916 from mjstapp/fix_gmtime

*: use gmtime_r exclusively

diff --cc bgpd/bgp_vty.c
Simple merge

diff --cc bgpd/bgpd.c
Simple merge

diff --cc lib/bfd.c
Simple merge

diff --cc zebra/zebra_vty.c
Simple merge

diff --cc zebra/zserv.c
Simple merge