Patch from cypherpunks. Fixes bug 20710; bugfix on 0.2.5.5-alpha.

It had been a directory authority since 0.2.1.20.

Issues noted by cypherpunks on #18162

This closes bug 18162; bugfix on a45b1315, which fixed a related
issue long ago.

In addition to the #18162 issues, this fixes a signed integer overflow
in smarltist_add_all(), which is probably not so great either.

Conflicts:
	src/or/config.c

teor (Tim Wilson-Brown) authored 9 years ago and Nick Mathewson committed 9 years ago

This new identity key was changed on 18 November 2015.

There was a dead check when we made sure that an array member of a
struct was non-NULL.  Tor has been doing this check since at least
0.2.3, maybe earlier.

Fixes bug 17781.