LUCreateInstance unlock all nodes mid-way
LUCreateInstance unlock all nodes mid-way

When creating a new instance, after saving the instance data to the config file
and creating the disks, but before waiting for sync and installing the OS, we
release the node locks, to allow for more instance creations to proceed in
parallel.

Reviewed-by: iustinp


dimara/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,ganeti/ganeti,yiannist/ganeti,leshchevds/ganeti,dimara/ganeti,onponomarev/ganeti,leshchevds/ganeti,apyrgio/ganeti,andir/ganeti,mbakke/ganeti,leshchevds/ganeti,yiannist/ganeti,apyrgio/ganeti,ganeti/ganeti,andir/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,bitemyapp/ganeti,mbakke/ganeti,ganeti/ganeti,grnet/snf-ganeti,apyrgio/snf-ganeti,andir/ganeti,grnet/snf-ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1