Don't assume every AWS VPC has tags

The default VPC has no tags (by default), so we should use get()
Default ENABLE_CLUSTER_MONITORING to false

Otherwise kube-down fails because the variable is not defined
Add functions to get kubelet directories.

Gets rid of some magic constants and makes volume plugins (coming later)
cleaner.
Run e2e tests in deterministic random order

Currently, we run the e2e tests in whatever order readdir happens to
return, which is random on some filesystems, name sorted on others,
create order on others, etc. Eventually, we may want to be
automatically hermetic between e2e tests (especially as we introduce
more resource destructive tests), but until then, it would be useful
if we permute the test order randomly between runs to ensure that
developers don't accidentally rely on a particular order. This
introduces a form of forced hermeticism, since improper state cleanup
from one test may not perturb a given test, but there's probably *a*
test in the suite that the order will perturb, so the RNG will find
that order eventually.

Adds logging of the generated seed, and an --orderseed argument that
can be used to re-run in the same order. Also sorts the pass/fail list
now for easier human reading.
Merge pull request #2782 from zmerlynn/e2e.shuffle

Run e2e tests in deterministic random order
Merge pull request #2667 from thockin/klet-dirs

Kubelet directory-name builder funcs
Add --pushup to e2e.go

Silly but hopefully memorable name for an option to --push OR --up
depending on cluster state.
Add util to validate namespaced names
Merge pull request #2795 from zmerlynn/pushup

Add --pushup to e2e.go
Merge pull request #2653 from justinsb/default_cluster_monitoring

Default ENABLE_CLUSTER_MONITORING to false
Merge pull request #2652 from justinsb/default_vpc_has_no_tags

Don't assume every AWS VPC has tags
Improve error reporting

Follow-up of changes introduced in commit 72c922668fefc1cf671d9c9e38ebf22a22a80dcf
Merge pull request #2801 from VojtechVitek/checkError

Improve error reporting
Fix e2e.
Merge pull request #2802 from brendandburns/fix

Fix e2e.
Merge pull request #2779 from thockin/qualname

Add util to validate namespaced names
x509 request authenticator