How can I temporarily adhere plastic conduit to a brick wall?
Try some 3M Extreme mounting tape http://amzn.to/2h7cIi6
If there is any leftover tape on the wall when you remove it, use some adhesive remover on it.

The other option would be to attach some legs on the pipe so that it can be physically supported by the ground. Or wire/rope it to anything that protrudes from the brick wall.