Improve integration test

Use some constants for tokens.
Refactor tokenfile creation to function.
Reorder some test cases to make lookups follow creates so they succeed.
Add expected status code to test cases (some are not quite what expected,
so filed bugs #2112, #2113, #2114)
Check expected status codes.
Close Body after each iterations so that we don't run out of file handles
  when I add even more test cases in the next PR.
Handle that it is unpredictable whether status 200 or 202 is returned.
Add net-tools pre-req to Vagrant instructions

Adds a note mentioning that `net-tools` are required for bridging VirtualBox's host networks. Added a similar note under the troubleshooting section.
Add support for a 'log' command to kubectl.
Make endpoints return 400 instead of 500
Fix local cluster scripts
Fix healthz test error handling
Removed 'Metadata' from all types
Merge pull request #2102 from markturansky/v1beta3_refactor_metadata

Refactor v1beta3 - Refactor 'Metadata' to ObjectMeta from all types
Merge pull request #2109 from smarterclayton/test_cmd_can_fail_on_public_addr

test-cmd.sh can fail if public IP not available
Merge pull request #2130 from claire921/refactor_healthz_test

Fix healthz test error handling
Merge pull request #2127 from colemickens/patch-1

Add net-tools pre-req to Vagrant instructions
Merge pull request #2116 from erictune/improve_auth_integ

Improve integration test
Change a spammy log to V(3)
Merge pull request #2124 from brendandburns/fix

Make endpoints return 400 instead of 500
Merge pull request #2128 from brendandburns/kubelet

Add support for a 'log' command to kubectl.
Merge pull request #2125 from brendandburns/flake

Deflake the TestCreate test, by adding an explicit wait.
Fix TestAuthModeAlwaysAllow.

Fix #2137
Merge pull request #2138 from dchen1107/master

Fix TestAuthModeAlwaysAllow.
Fixes #1612 kubelet should fail to start if it cannot create rootDir
Merge pull request #2132 from erikstmartin/kubelet-rootdir-fix

Fixes #1612 kubelet should fail to start if it cannot create rootDir