update_build_changes.sh: Create target directories if needed

:Release Notes:
When creating new build someone had to manually create initial
baselines on server, this will create directory structure
automatically.

:Detailed Notes:

:Testing Performed:
Only build tested.

:QA Notes:
No change in image.

:Issues Addressed:
[ES-113] Convert verification builds to use build.sh

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I0fe0c005a9fda8f444242307f6702f7414301aae
Reviewed-on: https://g2g.palm.com/3359
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Susan Montooth <susan.montooth@lge.com>