Bug 1623278 - Workaround to make gcc 8.3.0 happy. r=jstutte

Depends on D65547

Differential Revision: https://phabricator.services.mozilla.com/D69170

--HG--
extra : moz-landing-system : lando

dom/indexedDB/ActorsParent.cpp

@@ -17325,7 +17325,7 @@ nsresult QuotaClient::InitOrigin(PersistenceType aPersistenceType,
     // If there is an unexpected directory in the idb directory, trying to
     // delete at first instead of breaking the whole initialization.
     if (NS_WARN_IF(!databaseFilenames.GetEntry(subdirNameBase)) &&
-        NS_WARN_IF(NS_FAILED(DeleteFilesNoQuota(directory, subdirName)))) {
+        NS_WARN_IF((NS_FAILED(DeleteFilesNoQuota(directory, subdirName))))) {
       REPORT_TELEMETRY_INIT_ERR(kQuotaExternalError, IDB_GetEntry);
       return NS_ERROR_UNEXPECTED;
     }