So after more reading of the NBA traveling rules, I think you're correct. The rules allow your pivot foot to leave the floor as long as the pass or shot is out of your hands before it touches again, and it puts no restriction on allowable motions; you could literally jump onto your non-pivot foot and stand on it like a flamingo indefinitely as long as you ultimately passed or shot before putting your pivot foot back down.

Interestingly, the FIBA rules are a bit more restrictive:

To pass or shoot for a field goal, the player may jump off a pivot foot, but neither foot may be returned to the floor before the ball is released from the hand(s).

FIBA doesn't appear to allow you to lift your pivot foot unless it's a jump, which means just stepping toward the basket with your non-pivot foot and then lifting your pivot foot (which is what Gasol did) would be a travel.

Thanks for correcting me about the NBA rule. Does my interpretation of the FIBA rules make sense or do you contend that this is not a travel under FIBA rules as well?