fix 1238: Allow individual cloud-init user-data at each VM

both for instantiation and scaling. In that way every VM will have
individual jinja2 parsing with its own variables that includes
among other the count_index

Change-Id: I0cfdc9da2f71816273dbf37a03e418aa985d523c
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>