Show generic error instead of wrong error object.

Closes #1147.

src/app/effects/query.ts

@@ -192,7 +192,8 @@ export class QueryEffects {
                       return new queryActions.SetQueryResultAction(result, response.windowId);
                     }),
                     catchError((error: any) => {
-                      let output = 'Server Error';
+                      let output = 'Server Error. Check that your server is up and running.' +
+                      ' You can check the console for more details on the network errors.';
 
                       debug.log(error);
                       requestStatusCode = error.status;

src/app/services/gql/gql.service.ts

@@ -169,9 +169,12 @@ export class GqlService {
         if (err.error instanceof ErrorEvent) {
           // A client-side or network error occurred. Handle it accordingly.
           debug.error('An error occurred:', err.error.message);
+        } else if (err.error instanceof ProgressEvent) {
+          debug.error('Progress event error', err.error);
         } else {
           // The backend returned an unsuccessful response code.
           // The response body may contain clues as to what went wrong,
+          debug.error(err.error);
           debug.error(
             `Backend returned code ${err.status}, ` +
             `body was: ${err.error}`);
@@ -189,21 +192,6 @@ export class GqlService {
     );
   }
 
-  /**
-   * Send graphQL request and return the response
-   * @param query
-   * @param vars
-   */
-  send(query: string, vars?: string, selectedOperation?: string, files?: fromVariables.FileVariable[], withCredentials?: boolean) {
-    return this._send({
-      query,
-      variables: vars,
-      selectedOperation,
-      files,
-      withCredentials,
-    }).pipe(map(res => res.body));
-  }
-
   sendRequest(url: string, opts: SendRequestOptions) {
     const files = opts.files && opts.files.length ? opts.files.filter(file => file && file.data instanceof File && file.name) : undefined;