Merge pull request #63550 from juanvallejo/jvallejo/move-cached-discovery

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

move cached_discovery to client-go/discovery

**Release note**:
```release-note
NONE
```

Moves the cmd/util CachedDiscoveryClient to client-go

cc @soltysh @deads2k

Kubernetes-commit: f2ea83bef88f9d2783abe0c00de563db13ec04f4

vendor/github.com/gregjones/httpcache/.travis.yml

@@ -0,0 +1,18 @@
+sudo: false
+language: go
+go:
+  - 1.6.x
+  - 1.7.x
+  - 1.8.x
+  - master
+matrix:
+  allow_failures:
+    - go: master
+  fast_finish: true
+install:
+  - # Do nothing. This is needed to prevent default install action "go get -t -v ./..." from happening here (we want it to happen inside script step).
+script:
+  - go get -t -v ./...
+  - diff -u <(echo -n) <(gofmt -d .)
+  - go tool vet .
+  - go test -v -race ./...