Fix Bug 2012 use existing volumes as instantiation parameters

RO processes the existing vim-volume-id which is provided through the
instantation parameters, then they are consumed while creating the new VDUs.

Change-Id: Ic3bd71ac7679ab0ccbe9ee0847e4a8d3059c7c58
Signed-off-by: aticig <gulsum.atici@canonical.com>