provision/docker: remove debug println
provision/docker: fix the implementation of the ssh command

Floating around from tcp connection to http connection may cause some
loss. We're not interested in it. Let's play TCP.

Related to #853.
testing: add function for writting the token file
cmd: fix call to RollbackFile

I've renamed this function, so it makes more sense.
cmd/tsuru-base: fix call to RollbackFile function

The same as 814ef5ce9bd17baf56e10814cd4ca6f1d12198bc.
provision/docker: fix call to RollbackFiles
provision/docker: use the function for creating the token file

Should fix the build :)

Related to #853.