Dont generate ip_start for window upgrade if default ip address is used

There are two scenarios for windows upgrade that we need to take care of:
a). Hostname is specified on ip/ip_start/service_register.bat
b) Default ip_address is used, no manual specification for ip address

NS_server uses the following logic to identify the appropriate ip address to use:
1. if no ip/ip_start found, a default ip address will be picked up and it is open to change when joining a cluster.
2. if ip_start found, the found ip address will be used and honored even after joining a cluster
3. if ip file found, the associated ip address will be used, but it is open for change after joining a cluster

for case a, it should apply case 2 to have an ip_start file
for case b, it should apply case 3 to tell ns_server:
one, it is a upgrade case, all configuraiton and data should be kept after upgrade.
two, it is a default ip address case. the ip address is open to change after joining a cluster.

See CBSE-583 for a bug introduced for 2.0.1, i.e. always generating a ip_start to contain ip address.