opnfvdocs: Store colorado.2.0 documents in different location

opnfvdocs: Store colorado.2.0 documents in different location

This patch is a workaround until more proper mechanism is put in place.

The doc-version parameter is appended to default GS_URL, changing the
storage location of the documents from
    http://artifacts.opnfv.org/sfc/colorado/docs/bradys-cool-document.html
to
    http://artifacts.opnfv.org/sfc/colorado/2.0/docs/bradys-cool-document.html

Documents generated from master branch will be stored in same location such as
    http://artifacts.opnfv.org/sfc/docs/bradys-cool-document.html

Change-Id: Ibdd03a0dac14e44160c14fa0130d339c00e0adce
Signed-off-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>