tests/server/resolve.c: fix deprecation warning

MSVC warns that gethostbyname is deprecated. Always use getaddrinfo
instead to fix this when IPv6 is enabled, also for IPv4 resolves. This
is also consistent with what libcurl does.

Closes https://github.com/curl/curl/pull/1682

tests/server/resolve.c

@@ -107,16 +107,8 @@ int main(int argc, char *argv[])
   atexit(win32_cleanup);
 #endif
 
-  if(!use_ipv6) {
-    /* gethostbyname() resolve */
-    struct hostent *he;
-
-    he = gethostbyname(host);
-
-    rc = !he;
-  }
-  else {
 #ifdef ENABLE_IPV6
+  if(use_ipv6) {
     /* Check that the system has IPv6 enabled before checking the resolver */
     curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
     if(s == CURL_SOCKET_BAD)
@@ -125,28 +117,38 @@ int main(int argc, char *argv[])
     else {
       sclose(s);
     }
+  }
 
-    if(rc == 0) {
-      /* getaddrinfo() resolve */
-      struct addrinfo *ai;
-      struct addrinfo hints;
-
-      memset(&hints, 0, sizeof(hints));
-      hints.ai_family = PF_INET6;
-      hints.ai_socktype = SOCK_STREAM;
-      hints.ai_flags = AI_CANONNAME;
-      /* Use parenthesis around functions to stop them from being replaced by
-         the macro in memdebug.h */
-      rc = (getaddrinfo)(host, "80", &hints, &ai);
-      if(rc == 0)
-        (freeaddrinfo)(ai);
-    }
+  if(rc == 0) {
+    /* getaddrinfo() resolve */
+    struct addrinfo *ai;
+    struct addrinfo hints;
 
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = use_ipv6 ? PF_INET6 : PF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_CANONNAME;
+    /* Use parenthesis around functions to stop them from being replaced by
+       the macro in memdebug.h */
+    rc = (getaddrinfo)(host, "80", &hints, &ai);
+    if(rc == 0)
+      (freeaddrinfo)(ai);
+  }
 #else
+  if(use_ipv6) {
     puts("IPv6 support has been disabled in this program");
     return 1;
-#endif
   }
+  else {
+    /* gethostbyname() resolve */
+    struct hostent *he;
+
+    he = gethostbyname(host);
+
+    rc = !he;
+  }
+#endif
+
   if(rc)
     printf("Resolving %s '%s' didn't work\n", ipv_inuse, host);