smbserver.py/dictserver.py were explicitly using localhost/127.0.0.1 for
binding the server which when we were running the tests with a separate
HOSTIP and CLIENTIP had failures verifying the server from the device we
were testing.
This changes them to take the address from runtests.py and default to
localhost/127.0.0.1 if none is given.
Closes#4048