Datastream support fix

[petardz]

Issue #, if available:

Description of changes: Fixed handling of index name starting with dot. Fixed mapping parsing bug when interim node was "properties"

CheckList: [ ] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[dblock]

Want to rebase and finish this @petardz?

[Catch All Triage - 1, 2, 3, 4]