cmd_exec() sometimes returned the command in the output albeit
echo_cmd=False was specified, notably if the command contained a
newline.
Signed-off-by: Jan Lindemann <jan@janware.com>
It's wrong to use line buffering in fdopen(..., ".b"), there's no
such thing as a line in binary data, also see
https://bugs.python.org/issue32236
Signed-off-by: Jan Lindemann <jan@janware.com>
