The drain pipe in the bottom rear of my washer leaked when I moved to clean floor behind it. When I removed clamp, about a quart of water flowed out which I guess means it did not drain completely.

What should I do?

I'm guessing that moving the washer bumped it where the clamp is, and some leaked out. That there is a quart or so in the pipes is OK... that's just because the discharge tube hole is up off the floor so high.

Clean it up, be sure the hose is clamped on tight - and run a short small load and watch it closely. I wouldn't be surprised that you find it's not leaking at all.

I did the those spins a few times. If I push the washer back to tight toward the wall, it drips when spinning. If I pull it out from the wall a few inches it doesn't. Problem is it is behind bifold doors in the kitchen and I have to keep moving it back and forth because I am trying to sell my house and want to keep those doors closed...

Then that connection is the issue. Pushing it back as far as you need to is causing the wall to push on the connection and loosten it.

I would try a local appliance parts store: describe the issue and ask them if they've got a special elbow to put on at the outlet of the washer that's more secure.

Or for a quick try yourself: If the clamp is the type you squeeze on with your hand, maybe take it off - squeeze it smaller so that it grips tighter, then put it back on.

Also, you might try something like this:
http://doityourself.com/store/6327712.htm so that you can screw it on real tight before shoving it back in against the wall.