Add ('rdb', 'stream', '--') to wrapper.
Uses -- to send args to subprocess. (This was the bug with original CL)

Note - to test this, we will have to push changes and revert
immediately if we notice any breakage.

Recipe-Nontrivial-Roll: build
Change-Id: Ibe46314c2f791a99c0e670ff6cc44f6f24fb9f70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2342254Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Erik Staab <estaab@chromium.org>
Commit-Queue: Saagar Sanghavi <saagarsanghavi@google.com>