Aborting when no valid files to push and clear log output

Check to abort and log output before adding `tty?`

There are two consequences of this change. First, `files_to_load` will abort
if there are no valid files. Before this change, spin would push to the
server.

Secondly, having `tty?` in the log output is a little confusing. This change
makes the log output more clear.