Use heat's default value for max_template_size
Use heat's default value for max_template_size

Instead of aligning value with tempest, make tempest use heat's default
value as that is what most people will be deploying with.

Change-Id: I77549f2b5e953ff712c50a2b372f6b04725d5eb0

j4/devstack,affo/devstack,CloudServer/devstack,noironetworks/devstack,richliu/devstack,costingalan/devstack,eharney/devstack,neerja28/Devstack_GlusterFS,virtualopensystems/devstack,avvocatodemarchis/devstack,bljgaurav/openstack-test,olivierlemasle/devstack,nawawi/openstack,dtroyer/devstack,TwinkleChawla/devstack,mssumanth/devstack,promptworks/devstack,wenhuizhang/devstack,olivierlemasle/devstack,rushiagr/devstack,jamielennox/devstack,dtroyer/devstack,bswartz/devstack,andrewrothstein/devstack,Millnert/contrail-devstack,mc2014/devstack,srics/devstack,pczerkas/devstack,prithivm/branch01,NaokiMiyata/devstack,herrsechs/devstack,pacinete/devstack,tianweizhang/devstack,HPCHub/devstack,Juniper/devstack,dirkmueller/devstack,nawawi/openstack,ozamiatin/devstack,ozamiatin/devstack,bswartz/devstack,Mahito/devstack,herrsechs/devstack,pombredanne/devstack,vishnugonela/devstack,varunarya10/devstack,bq-xiao/devstack,bigswitch/devstack,samgoon/devstack,atulpatil301/devstack,promptworks/devstack,JioCloud/devstack,innodee/openstackk,group-policy/devstack,liuquansheng47/devstack,mmasaki/devstack,vsham20/devstack,openstack-dev/devstack,TwinkleChawla/devstack,openstack-dev/devstack,eshnil2000/devstack,avvocatodemarchis/devstack,NaokiMiyata/devstack,bljgaurav/openstack-test,pombredanne/devstack,noironetworks/devstack,vsham20/devstack,sequenceiq/devstack,samgoon/devstack,costingalan/devstack,kplus/devstack-moonshot,affo/devstack,pacinete/devstack,parul24/devstack,williamthegrey/devstack,mmasaki/devstack,mc2014/devstack,mssumanth/devstack,sc68cal/devstack,parul24/devstack,liuquansheng47/devstack,BSJAIN92/OpenStack,group-policy/devstack,tianweizhang/devstack,thomasem/devstack,neerja28/Devstack_GlusterFS,vishnugonela/devstack,LoHChina/devstack,sc68cal/devstack,richliu/devstack,bq-xiao/devstack,flavio-fernandes/devstack,wenhuizhang/devstack,eharney/devstack,sequenceiq/devstack,Mahito/devstack,nuxeh/devstack,LoHChina/devstack,atulpatil301/devstack,flavio-fernandes/devstack,kplus/devstack-moonshot,nuxeh/devstack,thomasem/devstack,CloudServer/devstack,upadhyay-prashant/devstack,rushiagr/devstack,j4/devstack,bigswitch/devstack,varunarya10/devstack,andrewrothstein/devstack,dirkmueller/devstack,prithivm/branch01,HPCHub/devstack,upadhyay-prashant/devstack,yamt/devstack,pczerkas/devstack,BSJAIN92/OpenStack