After kegging a beer I only hook it up to co2. It doesn't go to the beer lines until it's fully carb'ed. And I've done this same thing a few times. Run a pint or two through it, you'll be just fine!*
*sanitizing is key in all parts of brewing, you'll never forget to sanitize a line again. Or you'll forget and pay for it later with ruined homebrew.
Primary: Centennial Blond | Kegged Carbonating: 3 Empty Kegs | Kegged: ESB, Pale Ale | Bottled: Red Ale, Black IPA, Hoppy Holidays (light red), IPA, Apfelwein