Ports: Use keyserver.ubuntu.com as .sig keyserver (SerenityOS#2535)

Increases the number of successfully building ports from
27 to 36 (of 56) on my system.

Ports/.port_include.sh

@@ -52,7 +52,9 @@ func_defined post_fetch || post_fetch() {
 fetch() {
  if [ "$auth_type" == "sig" ] && [ ! -z "${auth_import_key}" ]; then
  # import gpg key if not existing locally
- gpg --list-keys $auth_import_key || gpg --recv-key $auth_import_key
+ # The default keyserver keys.openpgp.org prints "new key but contains no user ID - skipped"
+ # and fails. Use a different key server.
+ gpg --list-keys $auth_import_key || gpg --keyserver hkps:https://keyserver.ubuntu.com --recv-key $auth_import_key
  fi
 
  OLDIFS=$IFS