fix drbd restore code so it can handle multiple volumes in single resour...

hi:
  this patch tried to fix two problems.
1. force create drbd metadata. the command have been tested in 8.3.16 and 8.4.5.
2. restore multiple volumes. when resource was activate (up or attach)  first time, next time the script use "drbdadm role" to check if the resource is already activate and skip the rest. so when restore multiple volumes,  the resource will be create/activate once.  the restore has been test  under 8.3.16 and 8.4.5 correctly.  under 8.4.5  "drbd attach" failed but it seems like a drbdadm bug. will report drbd upstream.