CURLOPT_RESOLVE: added

CURLOPT_RESOLVE is a new option that sends along a curl_slist with
name:port:address sets that will populate the DNS cache with entries so
that request can be "fooled" to use another host than what otherwise
would've been used. Previously we've encouraged the use of Host: for
that when dealing with HTTP, but this new feature has the added bonus
that it allows the name from the URL to be used for TLS SNI and server
certificate name checks as well.

This is a first change. Surely more will follow to make it decent.

lib/hostip.c

@@ -421,6 +421,9 @@ int Curl_resolv(struct connectdata *conn,
   /* See if its already in our dns cache */
   dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len+1);
 
+  /* free the allocated entry_id again */
+  free(entry_id);
+
   /* See whether the returned entry is stale. Done before we release lock */
   if( remove_entry_if_stale(data, dns) )
     dns = NULL; /* the memory deallocation is being handled by the hash */
@@ -433,9 +436,6 @@ int Curl_resolv(struct connectdata *conn,
   if(data->share)
     Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
 
-  /* free the allocated entry_id again */
-  free(entry_id);
-
   if(!dns) {
     /* The entry was not in the cache. Resolve it to IP address */