xenapi: set dhcp timeout on VM installation
xenapi: set dhcp timeout on VM installation

Set the DHCP timeout to 120 seconds during virtual machine installation.
Some users failed to run devstack, due to a low DHCP timeout setting.
The default value is 60 seconds. This change sets the value to 120 secs,
that should give enough time for most people.

Change-Id: I15fde45ed0d005c1a8621134eee6c3c338b5be5d

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