Adapt to new Kimchi authorization scheme

Recently Kimchi upstream changes the authorization scheme.
"tools.kimchiauth" does not verify admin_methods anymore. The validation
is moved to controller base class. So downstream should also change
accordingly.

Author: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>
Signed-off-by: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>
Signed-off-by: Christy Perez <christy@linux.vnet.ibm.com>