Use cluster VIP instead of controller IP in test 'Deploy Heat HA'

In the system test 'Deploy Heat HA' controller IP was used to connect 
to keystone, in this case, in HA mode, need to use cluster VIP 
instead of internal controller IP to successfully connection to keystone.

Closes-Bug: #1369412

Change-Id: I8ce6f9094396a8b203aa9fe8c4b05bd8675199e1
(cherry picked from commit bbfeb5d4bbaaa7e2e50f81d45c9e4c8619429e8d)
Merge "Use cluster VIP instead of controller IP in test 'Deploy Heat HA'" into stable/5.1