Don't update IP twice

- IP is updated in datasource#updateSession after successful login
- Remove no longer used DataSource#updateIp

src/main/java/fr/xephi/authme/datasource/CacheDataSource.java

@@ -229,15 +229,6 @@ public class CacheDataSource implements DataSource {
         return result;
     }
 
-    @Override
-    public boolean updateIp(String user, String ip) {
-        boolean result = source.updateIp(user, ip);
-        if (result) {
-            cachedAuths.refresh(user);
-        }
-        return result;
-    }
-
     @Override
     public List<PlayerAuth> getAllAuths() {
         return source.getAllAuths();