Check for HttpErrorException instead of BackendException

* VuFind/Search/Solr/V3/ErrorListener.php: Check for
  HttpErrorException instead of BackendException.

module/VuFind/src/VuFind/Search/Solr/V3/ErrorListener.php

@@ -29,7 +29,7 @@
 
 namespace VuFind\Search\Solr\V3;
 
-use VuFindSearch\Backend\Exception\BackendException;
+use VuFindSearch\Backend\Exception\HttpErrorException;
 
 use Zend\EventManager\EventInterface;
 
@@ -76,7 +76,7 @@ class ErrorListener
         $backend = $event->getParam('backend');
         if (in_array($backend, $this->backends)) {
             $error  = $event->getTarget();
-            if ($error instanceOf BackendException) {
+            if ($error instanceOf HttpErrorException) {
                 $reason = $error->getResponse()->getReasonPhrase();
                 if (stristr($error, 'org.apache.lucene.queryParser.ParseException')
                     || stristr($error, 'undefined field')

module/VuFind/tests/unit-tests/src/Search/Solr/V3/ErrorListenerTest.php

@@ -31,7 +31,7 @@ namespace VuFindTest\Search\Solr\V3;
 
 use VuFind\Search\Solr\V3\ErrorListener;
 
-use VuFindSearch\Backend\Exception\BackendException;
+use VuFindSearch\Backend\Exception\HttpErrorException;
 
 use Zend\EventManager\Event;
 use Zend\Http\Response;
@@ -60,7 +60,7 @@ class ErrorListenerTest extends TestCase
     {
         $response  = $this->createResponse('solr3-parse-error');
 
-        $exception = BackendException::createFromResponse($response);
+        $exception = HttpErrorException::createFromResponse($response);
         $params    = array('backend' => 'test');
         $event     = new Event(null, $exception, $params);
         $listener  = new ErrorListener(array('test'));
@@ -77,7 +77,7 @@ class ErrorListenerTest extends TestCase
     {
         $response = $this->createResponse('solr3-undefined-field-error');
 
-        $exception = BackendException::createFromResponse($response);
+        $exception = HttpErrorException::createFromResponse($response);
         $params    = array('backend' => 'test');
         $event     = new Event(null, $exception, $params);
         $listener  = new ErrorListener(array('test'));