alexzielenski: fix race in aggregated discovery controller

JobBuild
cff4d075
01-26 01:21		 115302
01-24 22:34		 08cb6d3d
01-24 22:32
pull-kubernetes-conformance-kind-ga-only-parallel 1618490520089137152 1618059426420232192 1618013807810973696
pull-kubernetes-dependencies 1618490519820701696 1618059426164379648 1618013807538343936
pull-kubernetes-e2e-gce 1618490519866839040 1618466263565078528 1618418699411132416 1618385450823585792 1618381953843597312 1618346469360668672 1618310654165258240 1618264216899162112 1618059426218905600 1618013807584481280
pull-kubernetes-e2e-gce-100-performance 1618490520265297920 1618059426575421440 1618013807991328768
pull-kubernetes-e2e-kind 1618490519980085248 1618059426319568896 1618013807714504704
pull-kubernetes-e2e-kind-ipv6 1618490520034611200 1618059426374094848 1618013807764836352
pull-kubernetes-integration 1618490519921364992 1618059426269237248 1618013807655784448
pull-kubernetes-node-e2e-containerd 1618490520198189056 1618418699474046976 1618385450878111744 1618381953889734656 1618346469411000320 1618310654219784192 1618264216941105152 1618059426512506880 1618013807915831296
pull-kubernetes-typecheck 1618490520307240960 1618059426625753088 1618013808033271808
pull-kubernetes-unit 1618490520147857408 1618059426466369536 1618013807869693952
pull-kubernetes-verify 1618494916499869696 1618490521485840384 1618059427837906944 1618013809190899712
pull-kubernetes-verify-govet-levee 1618490520646979584 1618059427007434752 1618013808352038912