Handle non-zero exit code from git diff
Handle non-zero exit code from git diff

The check for a changed repo in setup_develop() 'git diff --exit-code'
returns a status of 1 when the repo has changes; trap that so errexit
does not abort the script.

Bug-Id: 1285780
Change-Id: Ic97e68348f46245b271567893b447fcedbd7bd6e

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