Adding test for hosttracker

- Check to see if host are add to the topology
- Check that host are deleted once mininet is stopped
- Change the init script to have predefine mac with --mac
- Add test to check host are deleted.

Change-Id: I2c0fe00be1d99fa3905617ae3b92c57cb1d98445
Signed-off-by: Christopher O'Shea <christopher.o.shea@ericsson.com>
Merge "Adding test for hosttracker"