Make ironic ssh check timeout configurable
Make ironic ssh check timeout configurable

On some environments, the current 10s timeout waiting for server
ssh-able is not enough. SSH session was killed before the command
executed by server and then break the whole stack.sh.

Change-Id: I4d842744793455d44a633dee8920a60552e8075e

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