afsocket: Memory leak fix

If the configuration stays the same during a reload, log_reader_set_peer_addr()
is already called and log_reader_set_peer_addr() doesn't unref its previous
peer_addr.

Signed-off-by: Tibor Benke <ihrwein@gmail.com>
Merge pull request #166 from ihrwein/f/afsocket-memory-leak-fix

afsocket: Memory leak fix