[CDH5] Add support for WITH GRANT OPTION/REVOKE GRANT OPTION

This change adds support for GRANT <privilege> TO <role> WITH GRANT OPTION which allows
delegating GRANT/REVOKE authority to non-admin users. Specifically, it allows users who
have been granted the specified role to execute GRANT/REVOKE statements on all child
objects. For example, you can now do something like:
GRANT ALL ON DATABASE foo TO role1 WITH GRANT OPTION
and everyone granted role1 will be able to execute GRANT/REVOKE statements on database
foo OR any of the tables in the database.
It also adds support for REVOKE GRANT OPTION FOR <privilege> FROM <role> which allows
removing a previous WITH GRANT OPTION without actually deleting the privilege.
Similar to GRANT/REVOKE statements, the actual authorization checks on whether a user
should/should not have privileges to execute these options is done at the Sentry Service
level.

Change-Id: I8757569a3bdb68414e315ef37d6845b1859eb758
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4377
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: jenkins