Rename Entry classes in HashMap and LinkedHashMap.

The name "Entry" was hiding interface Map.Entry so code
that did stuff like :

  HashMap.Entry<K, V> foo : map.entrySet()

would break. Moreover, that naming scheme confusing (with
interface Map.Entry, class HashMap.Entry and class
LinkedHashMap.Entry) and this change (IMO) improves readability.

Change-Id: Ie9ea96f9a8e4a4988bdc47f77117dc23922315b3
2 files changed