Suppress an error that ES occurs 'index_already_exists_exception'

lib/util/middlewares.js

@@ -289,6 +289,14 @@ exports.checkSearchIndicesGenerated = function(crowi, app) {
             debug('Index created.');
           }
           return searcher.addAllPages();
+        })
+        .catch((error) => {
+          if (error.message != null && error.message.match(/index_already_exists_exception/)) {
+            debug('Creating index is failed: ', error.message);
+          }
+          else {
+            console.log(`Error while building index of Elasticsearch': ${error.message}`);
+          }
         });
     }