Improve comments in checkSpace.pl to explain how to fix its warnings
Fix windows warning introduced by 0808ed83f9cf312abe229

This will fix the warning
   "/src/or/config.c:6854:48: error: unused parameter 'group_readable'"
that I introduced while fixing 12864.

Bug not in any released version of Tor.
Merge remote-tracking branch 'origin/maint-0.2.5'