use non-EventMachine Warden client
dea.discover is no longer used
Use a real patch level in .travis.yml
staging is now async.  still need to fix failing rails spec.
Integration tests are green again.
removed deprecated async flags
Revert "use non-EventMachine Warden client"

This reverts commit f8c7fa9d6e7a9d7c81f3537f18ad8ace93fbcc96.
Update submodules for test VM
Escape environment variables passed to staging
Update README to tell users that vagrant up must be run from dea_ng dir
Allow running apps with provided service instances.

[#50701663]
Delete useless test
Start instance in staging completion callback
Don't log that upload finished
Trigger after complete callback before uploading
Save droplet after staging in droplet registry
Staging and starting on the same DEA
Make droplet sha and download uri optional in start message
Increase ci evacuation delay config
Make staging test less flaky