fix three typos in comments
Build circuits more readily when DisableNetwork goes to 0

When Tor starts with DisabledNetwork set, it would correctly
conclude that it shouldn't try making circuits, but it would
mistakenly cache this conclusion and continue believing it even
when DisableNetwork is set to 0. Fixes the bug introduced by the
fix for bug 11200; bugfix on 0.2.5.4-alpha.
Merge remote-tracking branch 'origin/maint-0.2.5'