initial changes to fix current db

adding MetaStoreUtils import to HiveConf

adding constants to HiveConf
moving DEFAULT db variables to HiveConf
HIVE-4171 - hcat changes
HIVE-4171 - adding test case
HIVE-4171 - fix hcat checkstyle issues
HIVE-4171 - adding default database conf param to restricted list
HIVE-4542.1.patch