Moving horizon compression offline
Moving horizon compression offline

Making the horizon scss compilation and compression happen offline.
Potentially fixing an issue with parallel compression in devstack.

Related-Bug: #1345955
Change-Id: I066c80e06a92302a3f8dc5fd45d127fbde6cf99c

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