Use 100 servers per hpcloud network:router pair.

The error rate for hpcloud 1.1 when under load with 190 servers per
network:router pair exceeded the success rate. Reduce the number of
servers to 100 in each network:router pair to see if this handles load
better.

Change-Id: I91327d8452e3df30de22ee635fcd68fbb7b24c7f