Allow adding network interfaces with specific IP addresses. It is possible that an interface can have multiple IP addresses assigned to it. Since the IP address is explicitly used to describe an LNet NID, we should allow specifying network interfaces via their IP addresses. Linux routing can route packets based on their source IP addresses differently. It is potentially possible that routing can be setup such that Lustre traffic can be routed different from other application traffic, even though both are originating from the same interface.
Bug
Minor
