Improve Ranger database schema import logic and make it more robust

Problem Statement: Ranger installation process should handle concurrent import of DB schema as concurrent execution of db schema files can lead to an inconsistent state of data and application.

Proposed Solution : Before importing db schema file; installation process will insert status in x_db_version_h table with active='N' value. If schema will get created/imported successfully then status of the schema creation flag will be set to 'Y' else status row from x_db_version_h will be deleted. If the Ranger DB schema is being imported then the active column will have the value 'N' and no other process will be allowed to import that file.