Bug 736541: Remove unused variable 'parentId' from nsNavHistory.cpp to fix build warning. r=mak

toolkit/components/places/nsNavHistory.cpp

@@ -4418,11 +4418,9 @@ nsNavHistory::FilterResultSet(nsNavHistoryQueryResultNode* aQueryNode,
         nodeIndex > 0 && aSet[nodeIndex]->mURI == aSet[nodeIndex-1]->mURI)
       continue;
 
-    PRInt64 parentId = -1;
-    if (aSet[nodeIndex]->mItemId != -1) {
-      if (aQueryNode && aQueryNode->mItemId == aSet[nodeIndex]->mItemId)
-        continue;
-      parentId = aSet[nodeIndex]->mFolderId;
+    if (aSet[nodeIndex]->mItemId != -1 && aQueryNode &&
+        aQueryNode->mItemId == aSet[nodeIndex]->mItemId) {
+      continue;
     }
 
     // Append the node only if it matches one of the queries.