Fixed a bug when removing a file attached to multiple requests.

application/modules/requests/models/RequestModel.php

@@ -724,8 +724,13 @@ class Requests_RequestModel extends Unl_Model
         }
         $sql = $db->quoteInto('DELETE FROM creqRequestFiles WHERE requestFileId IN (?)', $requestFileIds);
         $db->query($sql);
-        $sql = $db->quoteInto('DELETE FROM creqFiles WHERE fileId IN (?)', $fileIds);
-        $db->query($sql);
+        try {
+	        $sql = $db->quoteInto('DELETE FROM creqFiles WHERE fileId IN (?)', $fileIds);
+	        $db->query($sql);
+        } catch (Zend_Db_Statement_Exception $e) {
+        	// If the file is used by multiple requsets, an integrity exception will be thrown.
+        	// We should just ignore it since it turns out we didn't want to delete this file anyway.
+        }
     }
 
     static protected function _saveFileToDisk($data)