update cinder's key permission to allow nova snapshots
update cinder's key permission to allow nova snapshots

Preparing the field for this patch:

https://review.openstack.org/205282

The client.cinder key needs to have write permission to the glance pool
in order to complete the snapshot process.

Change-Id: I98f16167db864ffd14e8c3dd5dec81fc16245448

thomasem/devstack,pacinete/devstack,avvocatodemarchis/devstack,avvocatodemarchis/devstack,parul24/devstack,noironetworks/devstack,atulpatil301/devstack,Mahito/devstack,eharney/devstack,HPCHub/devstack,bq-xiao/devstack,bigswitch/devstack,nawawi/openstack,olivierlemasle/devstack,Mahito/devstack,openstack-dev/devstack,upadhyay-prashant/devstack,prithivm/branch01,dtroyer/devstack,thomasem/devstack,liuquansheng47/devstack,atulpatil301/devstack,liuquansheng47/devstack,upadhyay-prashant/devstack,varunarya10/devstack,openstack-dev/devstack,dirkmueller/devstack,TwinkleChawla/devstack,ozamiatin/devstack,group-policy/devstack,mssumanth/devstack,pombredanne/devstack,vishnugonela/devstack,vsham20/devstack,pczerkas/devstack,richliu/devstack,mc2014/devstack,HPCHub/devstack,richliu/devstack,pombredanne/devstack,mssumanth/devstack,pczerkas/devstack,pacinete/devstack,bswartz/devstack,prithivm/branch01,dtroyer/devstack,varunarya10/devstack,vsham20/devstack,TwinkleChawla/devstack,samgoon/devstack,noironetworks/devstack,bswartz/devstack,bigswitch/devstack,bq-xiao/devstack,group-policy/devstack,nawawi/openstack,eharney/devstack,samgoon/devstack,vishnugonela/devstack,parul24/devstack,costingalan/devstack,olivierlemasle/devstack,dirkmueller/devstack,costingalan/devstack,mc2014/devstack,ozamiatin/devstack