dns utility does not compile on linux

[rspencer01]

Describe your issue

Commit c2c040f introduced a breaking change for Linux compilations.

Describe what you did:

cargo run --bin dns

Describe expected outcome

DNS utility compiles and runs.

Describe what happened

Compilation failed due to dependency on windows-only crate ipconfig.

Describe why this is important

It is well known that utility-belt is a mission-critical toolkit. Failure of any one piece may result in confusion, puzzlement and coffee going cold. More importantly, the dns utility is known to be more reliable on Robert's Laptop than the system dns service and is thus critical for testing the system service and cursing ubuntu's long release cycles.