fix some warnings in public headers (#486)

* fix two compile warnings in public headers

both warnings have to do with variable
name shadowing

include/yaml-cpp/node/detail/impl.h

@@ -132,8 +132,8 @@ inline bool node_data::remove(const Key& key, shared_memory_holder pMemory) {
   if (m_type != NodeType::Map)
     return false;
 
-  kv_pairs::iterator it = m_undefinedPairs.begin();
-  while (it != m_undefinedPairs.end()) {
+  for (kv_pairs::iterator it = m_undefinedPairs.begin();
+       it != m_undefinedPairs.end();) {
     kv_pairs::iterator jt = std::next(it);
     if (it->first->equals(key, pMemory))
       m_undefinedPairs.erase(it);

include/yaml-cpp/node/detail/node.h

@@ -106,9 +106,9 @@ class node {
   node_iterator end() { return m_pRef->end(); }
 
   // sequence
-  void push_back(node& node, shared_memory_holder pMemory) {
-    m_pRef->push_back(node, pMemory);
-    node.add_dependency(*this);
+  void push_back(node& input, shared_memory_holder pMemory) {
+    m_pRef->push_back(input, pMemory);
+    input.add_dependency(*this);
   }
   void insert(node& key, node& value, shared_memory_holder pMemory) {
     m_pRef->insert(key, value, pMemory);