修改httpdns的IP直连SSL认证问题 review by 小熊

@@ -591,7 +591,11 @@ willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challe
     }
     
     if ([challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]) {
-        if ([self.securityPolicy evaluateServerTrust:challenge.protectionSpace.serverTrust forDomain:challenge.protectionSpace.host]) {
+        NSString* host = [[self.request allHTTPHeaderFields] objectForKey:@"Host"];
+        if (!host) {
+            host = self.request.URL.host;
+        }
+        if ([self.securityPolicy evaluateServerTrust:challenge.protectionSpace.serverTrust forDomain:host]) {
             NSURLCredential *credential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust];
             [[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
         } else {