Retries on ingest_upload errors

[curlup]

By default

On rare occasions, a function might exit prematurely due to an internal error, and by default the function might or might not be automatically retried.

More typically, a background function may fail to successfully complete due to errors thrown in the function code itself. 

I suggest we add retry to the deployment:

cidc-cloud-functions/.travis.yml

Lines 51 to 55 in da73261

	script: bash deploy/pubsub.sh ingest_upload uploads .env.staging.yaml
	on:
	branch: master
	- provider: script
	script: bash deploy/pubsub.sh ingest_upload uploads .env.prod.yaml

Here are best practices on retries:
https://cloud.google.com/functions/docs/bestpractices/retries#functions-tips-infinite-retries-python