Allocate and deallocate ips one-by-one

The script is now allocating and deallocating ips one-by-one
instead of allocating all and then realising all

Change-Id: Ic53a651c8c4b0c3279f7f4cf6928a2041bd47f54
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>