Add git update tag support
Add git update tag support

Change-Id: I5ce1f05186d05b9cf0ccd74708af926ba054d2f0

wenhuizhang/devstack,inkerra/devstack,vishnugonela/devstack,NaokiMiyata/devstack,pczerkas/devstack,parul24/devstack,bswartz/devstack,andrewrothstein/devstack,mc2014/devstack,Millnert/contrail-devstack,vsham20/devstack,thomasem/devstack,nuxeh/devstack,pacinete/devstack,bq-xiao/devstack,atulpatil301/devstack,dirkmueller/devstack,j4/devstack,costingalan/devstack,j4/devstack,eharney/devstack,sc68cal/devstack,ykaneko/devstack,promptworks/devstack,sc68cal/devstack,kplus/devstack-moonshot,herrsechs/devstack,andrewrothstein/devstack,ykaneko/devstack,ozamiatin/devstack,mssumanth/devstack,nati/devstack_public,CiscoSystems/devstack,NaokiMiyata/devstack,olivierlemasle/devstack,LoHChina/devstack,eharney/devstack,pacinete/devstack,dirkmueller/devstack,TwinkleChawla/devstack,dtroyer/devstack,varunarya10/devstack,bq-xiao/devstack,parul24/devstack,nawawi/openstack,thomasem/devstack,richliu/devstack,noironetworks/devstack,HPCHub/devstack,TwinkleChawla/devstack,williamthegrey/devstack,cloudbuilders/devstack,bigswitch/devstack,tianweizhang/devstack,group-policy/devstack,BSJAIN92/OpenStack,nttmcl/devstack_public,mmasaki/devstack,innodee/openstackk,bljgaurav/openstack-test,CloudServer/devstack,olivierlemasle/devstack,mssumanth/devstack,richliu/devstack,mmasaki/devstack,armando-migliaccio/devstack,pczerkas/devstack,ewindisch/raspi-devstack,rushiagr/devstack,kplus/devstack-moonshot,CloudServer/devstack,group-policy/devstack,prithivm/branch01,costingalan/devstack,tianweizhang/devstack,vishnugonela/devstack,avvocatodemarchis/devstack,samgoon/devstack,eshnil2000/devstack,deepakselvaraj/devstack,samgoon/devstack,wenhuizhang/devstack,virtualopensystems/devstack,neerja28/Devstack_GlusterFS,shootstar/devstacktest,ewindisch/raspi-devstack,r-mibu/devstack,citrix-openstack-build/devstack,noironetworks/devstack,flavio-fernandes/devstack,pombredanne/devstack,yamt/devstack,bljgaurav/openstack-test,varunarya10/devstack,Yuriy-Leonov/devstack,LoHChina/devstack,savi-dev/devstack,nttmcl/devstack_public,JioCloud/devstack,herrsechs/devstack,upadhyay-prashant/devstack,sequenceiq/devstack,openstack-dev/devstack,BSJAIN92/OpenStack,HPCHub/devstack,dtroyer/devstack,savi-dev/devstack,Juniper/devstack,prithivm/branch01,nuxeh/devstack,neerja28/Devstack_GlusterFS,sequenceiq/devstack,srics/devstack,cloudbuilders/devstack,liuquansheng47/devstack,Mahito/devstack,bswartz/devstack,promptworks/devstack,citrix-openstack-build/devstack,upadhyay-prashant/devstack,sstrato/devstack,Mahito/devstack,nawawi/openstack,rushiagr/devstack,pombredanne/devstack,flavio-fernandes/devstack,r-mibu/devstack,ozamiatin/devstack,mc2014/devstack,nati/devstack_public,affo/devstack,vsham20/devstack,affo/devstack,atulpatil301/devstack,jamielennox/devstack,openstack-dev/devstack,avvocatodemarchis/devstack,bigswitch/devstack,liuquansheng47/devstack