This change splits out discovery fields from JoinConfiguration by performing
the following changes:

- Introduce a BootstrapTokenDiscovery structure, that houses configuration
  options needed for bootstrap token based discovery.

- Introduce a FileDiscovery structure, that houses configuration options
  (currently only a single option) needed for KubeConfig based discovery.

- Introduce a Discovery structure, that houses common options (such as
  discovery timeout and TLS bootstrap token) as well as pointer to an instance
  of either BootstrapTokenDiscovery or FileDiscovery structures.

- Replace the old discovery related JoinConfiguration members with a single
  Discovery member.

This change is required in order to cleanup the code of unnecessary logic and
make the serialized JoinConfiguration more structured (and therefore, more
intuitive).
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>

[scheduler cleanup phase 1]: Move FakeCache to pkg/scheduler/internal…

Fixes golint for pkg/probe

Remove pod status.phase check from pod event handlers

kubectl factory client access: Moves remaining internal references to remaining callers.

port-forward listen on address

kubectl env resolve: copy core fieldpath and resource dependencies into kubectl

kubectl rollback: remove duplicated code for printing pod template

fix paths w shortcuts when copying from pods

Fixed subpath in containerized kubelet.

Addresses an issue where copying from a remote location containing path
shortcuts (podName:../../../tmp/foo) causes an index out of range panic.

Fix overwriting env variables in kube-apiserver manifest

IsNotMountPoint should return no error when the checked directory does not
exists - missing directory can't be mounted. Therefore containerized
kubelet should check if the target exists first before resolving symlinks.
EvalHostSymlinks() returns indistinguishible error in case the path does
not exist.

Pass server handler context to storage nodeGetter

Allow an empty "" runtimeHandler

Remove deprecated --etcd-quorum-read flag

util/config` packages; filenames and methods should be updated to use…

Promote pod's websocket based NodeConformance tests to Conformance

Remove superfluous MkdirAll from MakeTempDirOrDie

Remove conformance tag from flaky test

refactor index_test to compress the assertions and make consistent with store_test.go 

fix a few typographic errors in test utils file

After the call to ioutil.TempDir, the directory has already been
created, and MkdirAll therefore can't do anything.  The mode argument
in particular is misleading.

Allow inverted key/cert order in combined PEM file

certificate.FileStore only handles (cert, key) combined PEM files. This
PR allows (key, cert), which is what "openssl req -out foo.pem -keyout
foo.pem" generates.

kubectl rollback: remove legacyscheme dependency

Upgrade the release version info in CHANGELOG.md

Fix DS tests to set node selectors related annotations on test namespaces to empty.

Default extensions/v1beta1 Deployment's RevisionHistoryLimit to MaxInt32

Retry attaching multipath iSCSI volumes

Don't mount single path instead of multipath volumes and always wait until
at least 2 paths are available. Try up to 3 times to get all paths. Try 5
times to get at last 2 paths.