Remove generated files (auto tools).

Some of these were revived in 4c163b1e bc they were supposedly not
generated when running autogen.sh. That's not the case (any more) so
let's avoid checking in generated files.

Note that these files will be included in tar balls made from make
dist.
Keep Proxy-State attributes in all replies to clients.

Closes RADSECPROXY-52.
ChangeLog updates bc 1.6.3 is tagged.