initialize port to 0, wildcard address test fails on OSX

I happened to compile this on my mac.

```

PASS: http_test
PASS: tls_test
PASS: buffer_test
FAIL: address_test
PASS: cfg_tokenizer_test
PASS: config_test
PASS: functional_test
PASS: bad_request_test
PASS: connection_reset_test
make[4]: Nothing to be done for `all'.
============================================================================
Testsuite summary for sniproxy 0.1
============================================================================
# TOTAL: 9
# PASS:  8
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0
============================================================================
See tests/test-suite.log
============================================================================
make[3]: *** [test-suite.log] Error 1
make[2]: *** [check-TESTS] Error 2
make[1]: *** [check-am] Error 2
make: *** [check-recursive] Error 1

cat tests/address_test.log
display_address(0x7f8ca0403af0) returned "*:2", expected "*"


```

Not really sure if thats the real problem, but this makes the tests work.