balloon: remove leftover code

This code should not be here. I am 100 % positive that I removed it in my
testings, but I must have forgotten to git add the remove before I sent out the
patch and it ended up in tree.

This is simply a test leftover, it will have the effect of having threads to
loop forever and never waiting because the initial value won't be 0.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>