Improve account existance check for bongacams

common/src/main/java/ctbrec/sites/bonga/BongaCamsModel.java

@@ -409,4 +409,20 @@ public class BongaCamsModel extends AbstractModel {
             setOnlineState(OFFLINE);
         }
     }
+
+    @Override
+    public boolean exists() throws IOException {
+        Request req = new Request.Builder() // @formatter:off
+                .url(getUrl())
+                .header(USER_AGENT, Config.getInstance().getSettings().httpUserAgent)
+                .header(ACCEPT_LANGUAGE, Locale.ENGLISH.getLanguage())
+                .build(); // @formatter:on
+        try (Response response = getSite().getHttpClient().execute(req)) {
+            if (!response.isSuccessful() && response.code() == 404) {
+                return false;
+            } else {
+                return !response.request().url().toString().endsWith("_deleted");
+            }
+        }
+    }
 }