Fixes notice issue in PhraseModel, a=chris

diff --git a/src/models/PhraseModel.php b/src/models/PhraseModel.php
index 4ca3393e5..d4129f261 100755
--- a/src/models/PhraseModel.php
+++ b/src/models/PhraseModel.php
@@ -1468,8 +1468,8 @@ class PhraseModel extends ParallelModel
         $cnt = count($out_pages);
         if ($groups_with_docs) {
             for ($i = 0; $i < $cnt; $i++) {
-                if (!$out_pages[$i][self::IS_DOC] ||
-                    $out_pages[$i][self::LOCATION]) {
+                if (empty($out_pages[$i][self::IS_DOC]) ||
+                    !empty($out_pages[$i][self::LOCATION])) {
                     unset($out_pages[$i]);
                 }
             }