Bug 1548580 - Remove a startup warning in PermissionManager, r=Ehsan

Differential Revision: https://phabricator.services.mozilla.com/D29682

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

Author: bakulf

extensions/permissions/nsPermissionManager.cpp

@@ -1022,8 +1022,10 @@ nsresult nsPermissionManager::InitDB(bool aRemoveFile) {
   if (NS_FAILED(rv)) {
     rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
                                 getter_AddRefs(permissionsFile));
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_UNEXPECTED;
+    }
   }
-  NS_ENSURE_SUCCESS(rv, NS_ERROR_UNEXPECTED);
 
   rv = permissionsFile->AppendNative(NS_LITERAL_CSTRING(PERMISSIONS_FILE_NAME));
   NS_ENSURE_SUCCESS(rv, rv);