CppTools: fix infinite deep tree for "Included by"

"Included by" was infected by infinite deep tree in case of cyclic.

Change-Id: If84fe52399f49d52baa42d681ab125d10d89dd3e
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cppeditor/cppincludehierarchymodel.cpp

@@ -301,7 +301,11 @@ void CppIncludeHierarchyModel::buildHierarchyIncludedBy_helper(const QString &fi
                                                                             isCyclic);
                 item->setLine(includeFile.line());
                 parent->appendChild(item);
-                buildHierarchyIncludedBy_helper(filePathFromSnapshot, item, cyclic, false);
+
+                if (isCyclic)
+                    continue;
+                else
+                    buildHierarchyIncludedBy_helper(filePathFromSnapshot, item, cyclic, false);
             }
         }
     }