Add cc uploader configurable drain timeout

[kathap]

• Add capi.cc_uploader.cc_uploader_drain_timeout_in_minutes (type: time, default: 15) to job spec
• Inject --shutdownTimeoutInMinutes=<%= p("capi.cc_uploader.cc_uploader_drain_timeout_in_minutes") %> into bpm.yml.erb
• Update drain.sh.erb to read the same property, apply the timeout when waiting for PID exit
• Retain 15-minute fallback in the script for robustness against missing property values

Thanks for contributing to the capi_release. To speed up the process of reviewing your pull request please provide us with:

• A short explanation of the proposed change:
  Allow operators to tune how long the CC-Uploader waits for in-flight uploads to finish during drain by introducing a new BOSH property (capi.cc_uploader.cc_uploader_drain_timeout_in_minutes) with a sane default of 15 minutes, wiring it through both the BPM startup flags and the drain script.

• An explanation of the use cases your change solves
  Let operators configure how long CC-Uploader waits (with a default of 15 minutes) during VM shutdown so active uploads complete gracefully.

• Links to any other associated PRs
  Improve droplet upload draining cc-uploader#245

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• I have made this pull request to the develop branch

• [] I have run CF Acceptance Tests on bosh lite

[jochenehret]

So here the timeout is reached and the process has not yet exited. Is it correct to exit the drain script with 0 and send 0 to BOSH in that case?

[kathap]

Yes, in this case it is correct, the drain script is not failing, the upload is just taking too long, so we waited for 15 minutes and then we let bosh go ahead and stop the jobs, which adds another 60s waiting time. If the upload does not finish in that time, diego will send another upload request to another VM.

[jochenehret]

Looks good, just consider renaming the drain template file.