Integration test in test/bin/test-flux has rotted

[jpellizzari]

Repro steps:

1. Run make integration-test
2. Wait for it to time out

Expected:
It finishes

Actual:
It times out. Pod logs show git clone: fatal: Could not read from remote repository.

Root cause:
After #892, ssh config is written loaded into the container image from disk. In the integration test, we mount the known_hosts file to the /root/.ssh directory:
https://github.com/weaveworks/flux/blob/master/test/flux-deploy-all.yaml#L86

This overwrites the directory and nukes the ssh_config, which contains the location of the identity file mounted at /etc/fluxd/ssh/identity: https://github.com/weaveworks/flux/blob/master/docker/ssh_config

Setting StrictHostKeyChecking no and removing the volumeMount works around the issue, but that won't work long term.

Kubernetes issue: kubernetes/kubernetes#51165
Possible working configuration (although it is a slightly different use case): dshulyak/kubernetes.github.io@d58ba7b

[jpellizzari]

The fix should be to figure out how to mount the known_hosts file without writing over the entire /root/.ssh directory.

[squaremo]

#921 fixes that initial problem; there are others though, so it's not complete.

[ncabatoff]

I gave up trying to get this working without making substantial changes, so I rewrote it in Go, see flux-tester for details. I'm open to merging it back into this repo but I'm operating under the assumption that if you had wanted it done this way you would've done so.

[jpellizzari]

I did have the bash one working in this branch: https://github.com/weaveworks/flux/tree/824-parse-list

[kingdonb]

This was removed a while ago, in 58f8d0a