Deal with a few semi-leaks

setproctitle.c copies the working environment so that we can modify
$0 and have it show up in the ps list. We were not cleaning up these
items during teardown so we were triggering valgrind "reachable leak"
tests.

Similarly there were a couple of minor "definitely leaked" cases which
might have come up in the case of a changed config (but would not come
up under normal operating circumstances.)

After this patch valgrind says:

  "All heap blocks were freed -- no leaks are possible"

\o/