No, Iraq should disqualify Clinton from becoming President, but apparently all the "liberals" seem to be suffering from collective amnesia.
These purity tests are fun and all, but it's not like any Democrat in the future will be embarking on another Iraq. Hillary's vote and flip-flop are regrettable, but it won't be a problem in her hypothetical administration. Unreasonable ideological inflexibility is not going to cost us the woman who is (by far) our best bet at retaining the White House.
If she was in the minority of the party back in 2002 and defying Democratic leadership, it would be a different story. She wasn't a maverick on the issue; far too many Democrats made the wrong choice.
If they made the wrong choice before, they can make it again. The exact same situation won't come up again, but it's worth questioning whether politicians have taken the right lessons from it.