Call ENETUNREACH a case of NOROUTE, not a case of INTERNAL.

Found by cypherpunks; fix for a part of bug 10777; bugfix on 0.1.0.1-rc.
Don't treat END_STREAM_REASON_INTERNAL as total circuit failure

It can happen because we sent something that got an ENETUNREACH
response.

Bugfix on 0.2.4.8-alpha; fixes a part of bug 10777.
make EACCES survivable too.
Merge remote-tracking branch 'public/bug10777_nointernal_024' into maint-0.2.4
update changes file
Merge branch 'bug10777_netunreach_024' into maint-0.2.4