Tor helpers' launch error message contains useless whitespace
While playing with #5099 (moved), I noticed that the spawn error message that Tor uses to denote "launch failure" usually looks like this:
ERR: Failed to spawn background process - code 9/2
The whitespace between 'code' and '9/2' occurs because format_helper_exit_status()
writes the last part of that string in reverse order, after first populating it with whitespace.
That is mainly an aesthetics issue but it also bugs log_from_pipe()
since it uses tor_sscanf()
to parse the error message, but without taking the whitespace into account:
retval = tor_sscanf(buf, SPAWN_ERROR_MESSAGE "%x/%x",
&child_state, &saved_errno);