httpsrr: fix port detection

[Fullmetal5]

Initialize port to -1 in the Curl_https_rrinfo struct, else it is set to 0 during memset and makes curl think the HTTPS RR is for port 0.

[testclutch]

Analysis of PR #16409 at 2746cc3f:

Test http/test_31_vsftpds.py::TestVsFTPD::test_31_07_shutdownh_upload failed, which has NOT been flaky recently, so there could be a real issue in this PR.

Generated by Testclutch

[bagder]

Thanks!

[calvin2021y]

I get this error:

curl/lib/asyn-ares.c:846:15: error: member reference type 'struct Curl_https_rrinfo' is not a pointer; did you mean to use '.'?
  846 |     res->hinfo->port = -1;
      |     ~~~~~~~~~~^~
      |               .
curl/lib/asyn-ares.c:846:22: error: expression is not assignable
  846 |     res->hinfo->port = -1;
      |     ~~~~~~~~~~~~~~~~ ^