Conform heat_ims subnets with other testcases
Conform heat_ims subnets with other testcases

It will be enhanced in a second step to calculate options from configs.

Change-Id: I91738e1aaad9a7049df44f734c4190def62fff91
Signed-off-by: Cédric Ollivier <d48310251a4a484d041bc5d09a9ac4d86d20f793@orange.com>

opnfv/functest,opnfv/functest