Add support for using IPA with iSCSI
Add support for using IPA with iSCSI

This patch is adding a new boolean that can be toggled to indicate
that we should use the IPA ramdisk instead of the normal ramdisk when
deploying a node with the iSCSI methodology. Defaults to False.

Depends-On: Iaabc6ada729461f18d69ee12d01b9f1465944454
Change-Id: If4004078866d833eb946be40b6dfb204aa4a6840

dtroyer/devstack,herrsechs/devstack,ozamiatin/devstack,bigswitch/devstack,thomasem/devstack,pacinete/devstack,bq-xiao/devstack,neerja28/Devstack_GlusterFS,upadhyay-prashant/devstack,pacinete/devstack,group-policy/devstack,herrsechs/devstack,samgoon/devstack,bljgaurav/openstack-test,CloudServer/devstack,bswartz/devstack,prithivm/branch01,pczerkas/devstack,BSJAIN92/OpenStack,wenhuizhang/devstack,CloudServer/devstack,samgoon/devstack,vishnugonela/devstack,costingalan/devstack,mssumanth/devstack,noironetworks/devstack,TwinkleChawla/devstack,atulpatil301/devstack,LoHChina/devstack,neerja28/Devstack_GlusterFS,avvocatodemarchis/devstack,richliu/devstack,HPCHub/devstack,rushiagr/devstack,olivierlemasle/devstack,liuquansheng47/devstack,sequenceiq/devstack,Mahito/devstack,rushiagr/devstack,richliu/devstack,Mahito/devstack,kplus/devstack-moonshot,dtroyer/devstack,NaokiMiyata/devstack,atulpatil301/devstack,liuquansheng47/devstack,eharney/devstack,mc2014/devstack,bljgaurav/openstack-test,flavio-fernandes/devstack,vishnugonela/devstack,sequenceiq/devstack,pczerkas/devstack,nuxeh/devstack,mmasaki/devstack,bigswitch/devstack,vsham20/devstack,mssumanth/devstack,parul24/devstack,openstack-dev/devstack,LoHChina/devstack,nawawi/openstack,dirkmueller/devstack,eharney/devstack,TwinkleChawla/devstack,avvocatodemarchis/devstack,pombredanne/devstack,thomasem/devstack,costingalan/devstack,pombredanne/devstack,mmasaki/devstack,j4/devstack,parul24/devstack,upadhyay-prashant/devstack,dirkmueller/devstack,andrewrothstein/devstack,olivierlemasle/devstack,openstack-dev/devstack,varunarya10/devstack,nuxeh/devstack,noironetworks/devstack,j4/devstack,BSJAIN92/OpenStack,varunarya10/devstack,andrewrothstein/devstack,wenhuizhang/devstack,bq-xiao/devstack,nawawi/openstack,bswartz/devstack,mc2014/devstack,flavio-fernandes/devstack,ozamiatin/devstack,NaokiMiyata/devstack,vsham20/devstack,prithivm/branch01,group-policy/devstack,kplus/devstack-moonshot,HPCHub/devstack