Fix 40d23ed

Commit message correctly described intention but code was the opposite and would result in nil pointer dereference panic, same boolean inversion that #2979 was correcting. I'm more interested in the fact no test case exercises this code path to catch either of these, but that's a separate task.

Author: welwood08

dnscrypt-proxy/xtransport.go

@@ -363,7 +363,7 @@ func (xTransport *XTransport) rebuildTransport() {
 		}
 	}
 	transport.TLSClientConfig = &tlsClientConfig
-	if http2Transport, _ := http2.ConfigureTransports(transport); http2Transport == nil {
+	if http2Transport, _ := http2.ConfigureTransports(transport); http2Transport != nil {
 		http2Transport.ReadIdleTimeout = timeout
 		http2Transport.AllowHTTP = false
 	}