Use https as default scheme

app/src/main/java/eu/faircode/email/FragmentDialogOpenLink.java

@@ -150,12 +150,9 @@ public class FragmentDialogOpenLink extends FragmentDialogBase {
             else {
                 Uri g = Uri.parse(URLUtil.guessUrl(url));
                 String scheme = g.getScheme();
-                if (scheme != null) {
+                if (scheme == null || "http".equals(scheme))
-                    if ("http".equals(scheme))
                     scheme = "https";
                 uri = Uri.parse(scheme + "://" + _uri.toString());
-                } else
-                    uri = _uri;
             }
         } else
             uri = _uri;