Prevent possible double-free in ares_getaddrinfo() if ares_destroy() …

…is called

In the event that ares_destroy() is called prior to ares_getaddrinfo() completing,
it would result in an invalid read and double-free due to calling end_hquery() twice.

Reported By: Jann Horn @ Google Project Zero

ares_getaddrinfo.c

@@ -548,6 +548,7 @@ static void host_callback(void *arg, int status, int timeouts,
   else if (status == ARES_EDESTRUCTION)
     {
       end_hquery(hquery, status);
+      return;
     }
 
   if (!hquery->remaining)