Use net.JoinHostPort
Test rejection of bad JSON.
Fix crash in test
Merge pull request #261 from meirf/test_bad_json_rejection

Test rejection of bad JSON.
Merge pull request #258 from lavalamp/misc_cleanup

Use net.JoinHostPort
Watch and Get on the same Etcd key.

Kubelet was killing existing pods when creating a new one because new
files were being set as /registry/hosts/<machine>/pods/<id> and
/registry/hosts/<machine>/kubelet.