afsocket: Memory leak fix

If the configuration stays the same during a reload, log_reader_set_peer_addr()
is already called.

Signed-off-by: Tibor Benke <ihrwein@gmail.com>
I think it wouldn't so nice to drop a reference, then reuse it again. When the reference counter reaches 0,  the object is freed, then we increment the reference with 1.  

Maybe the right thing would be checking the equality of peer_addr and self->peer_addr. When they are equal we do nothing, otherwise drop the old reference and use the new peer_addr.