[vCenter] Fix the parameters duplicated in answer file

Also this patch consolidate the options to a single vcenter host
for Cinder and Nova.

Change-Id: Iff01770b82dfceda1b3c706fb8a4556b38ecb774
Fixes: rhbz#1061372, rhbz#1092008
Merge "[vCenter] Fix the parameters duplicated in answer file"