tools/ndns-daemon: fix bug that validator cannot fetch certificate

refs #2206

Change-Id: I10c69d95e6a5fd020038211ce419763fd62afcb3
mgmt: management tools

refs #2034

Change-Id: I43ff11e0aa7e67f6207e75f139b7417779590efc
tools: management tools

refs #2034

Change-Id: Ib110e2d0e1214c3e95408a7f4d4679395e519319