Issue #455 Restore the Location header in HEAD pre-flight responses

[ggalmazor]

Closes #455

What has been done to verify that this works as intended?

Run Aggregate and use curl to verify that the Location header is in the response of the HEAD. I verified the two that can be accessed without auth and expect that the third will work because it has been changed the same way.

$ curl -XHEAD -I http://localhost:8080/formUpload
HTTP/1.1 204 No Content
Date: mié, 24 abr 2019 08:26:05 GMT
X-OpenRosa-Version: 1.0
X-OpenRosa-Accept-Content-Length: 10485760
Location: http://localhost:8080/formUpload
Server: Jetty(9.2.22.v20170606)


$ curl -XHEAD -I http://localhost:8080/submission
HTTP/1.1 204 No Content
Date: mié, 24 abr 2019 08:26:11 GMT
X-OpenRosa-Version: 1.0
X-OpenRosa-Accept-Content-Length: 10485760
Location: http://localhost:8080/submission
Server: Jetty(9.2.22.v20170606)

Why is this the best possible solution? Were any other approaches considered?

This is the old code that's running in 1.7 slightly refactored into just one line.

Are there any risks to merging this code? If so, what are they?

It's a pretty straightforward change that doesn't affect any other behavior in Aggregate. I wouldn't expect any risk to merging this PR.

Do we need any specific form for testing your changes? If so, please attach one

No.

Does this change require updates to documentation? If so, please file an issue at https://github.com/opendatakit/docs/issues/new and include the link below.

No.

[ggalmazor]

@lognaturel, if we get this approved today and you think that the curl verifications I've made are enough QA testing, I can merge this PR and get it into the v2.0.3. I'll hold the release in the meantime.

[lognaturel]

Thank you, @ggalmazor! Agree this should get out ASAP so folks don't lose attachments.