addon support in rsync script
To support addons in validation tests, we need
SLES and SLED need to add addon tests during test, for this we need the current addons
rsync needs to sync them too (HA, GEO and SDK) and whenever a SLES or SLED test is scheduled, it
defines ISO_1=$CURRENT_SDK, ISO_2=$CURRENT_HA and ISO_3=$CURRENT_GEO and the backend will add them
all as drives. The tests then need to make sure they pick the right ISOs.