don't retry with www.{host}, as it's a minor security issue

if www.host gets hacked (e.g. a bad wordpress plugin), it could spread
to the matrix server running on a different host.

src/matrix/well-known.js

@@ -22,40 +22,22 @@ function normalizeHomeserver(homeserver) {
     }
 }
 
-function getRetryHomeserver(homeserver) {
-    const url = new URL(homeserver);
-    const {host} = url;
-    const dotCount = host.split(".").length - 1;
-    if (dotCount === 1) {
-        url.host = `www.${host}`;
-        return url.origin;
-    }
-}
-
 async function getWellKnownResponse(homeserver, request) {
     const requestOptions = {format: "json", timeout: 30000, method: "GET"};
-    let wellKnownResponse = null;
-    while (!wellKnownResponse) {
     try {
         const wellKnownUrl = `${homeserver}/.well-known/matrix/client`;
         return await request(wellKnownUrl, requestOptions).response();
     } catch (err) {
         if (err.name === "ConnectionError") {
-                const retryHS = getRetryHomeserver(homeserver);
-                if (retryHS) {
-                    homeserver = retryHS;
-                } else {
             // don't fail lookup on a ConnectionError,
             // there might be a missing CORS header on a 404 response or something,
             // which won't be a problem necessarily with homeserver requests later on ...
             return null;
-                }
         } else {
             throw err;
         }
     }
 }
-}
 
 export async function lookupHomeserver(homeserver, request) {
     homeserver = normalizeHomeserver(homeserver);