kidlj: Check "fields" arg for setNestedFieldNoCopy call and report error instead of panicking if this arg is omitted

JobBuild
106645
11-24 10:59
aec46472
11-24 10:58
pull-kubernetes-conformance-kind-ga-only-parallel 1463461931862986752
pull-kubernetes-dependencies 1463461931711991808
pull-kubernetes-e2e-gce-100-performance 1463461931946872832
pull-kubernetes-e2e-gce-ubuntu-containerd 1463687033741381632 1463461931741351936
pull-kubernetes-e2e-kind 1463461931804266496
pull-kubernetes-e2e-kind-ipv6 1463461931833626624
pull-kubernetes-integration 1463461931774906368
pull-kubernetes-node-e2e-containerd 1463461931917512704
pull-kubernetes-typecheck 1463461931976232960
pull-kubernetes-unit 1463461931892346880
pull-kubernetes-verify 1463687033774936064 1463461933356158976
pull-kubernetes-verify-govet-levee 1463461932513103872