Use 'true' instead of 'echo online'

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Tweak log levels for command execution

When running in non-verbose mode, which is the default, we were not
logging which commands were being executed. We were, however, logging
the stdout and stderr of every command executed. This was backwards.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Fix lots of linter errors

They were distracting.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>
Duplicate streams in copy_file_obj()

Since we are trying to read the source stream twice, we need to be able
to seek() it. However, paramiko BufferedFile objects do not implement
seek(). So, if necessary, copy the source stream to a StringIO.

Signed-off-by: Zack Cerza <zack.cerza@inktank.com>