Revert #61 once docker/cli#2934 gets released

[0x2b3bfa0]

Once https://github.com/docker/cli/pull/2934 gets released, the changes introduced with #61 won't be required anymore and should be reverted.

[dacbd]

@iterative/cml Is this something that should actually change at this point? aka not using a temp dir?

I feel it is pretty safe to close.

[casperdcl]

I'd prefer removal of redundant fixes