specify the UUID correctly

we could have also used the new swap UUID and edited the fstab, but
that would have required more steps:

 1. mount the filesystem
 2. edit fstab
 3. unmount

... and another thing to redo after the last resync.

By enforcing a UUID from the start, we don't need to edit the fstab at
all. I can't think of a compelling reson why reusing the UUID might be
a problem.

tsa/howto/ganeti.mdwn

@@ -242,6 +242,10 @@ Import procedure:
       TODO: make sure the memory line is in KiB and that the number
       makes sense.
 
+    * find the swap device UUID so we can recreate it later:
+
+          blkid -t TYPE=swap -s UUID -o value
+
  3. setup a copy channel, on the KVM host:
  
         ssh-agent bash
@@ -261,6 +265,7 @@ Import procedure:
         lvcreate -L 20GiB -n chiwui-root vg_ganeti
         qemu-img convert /srv/chiwui.torproject.org-root  -O raw /dev/vg_ganeti/chiwui-root
         lvcreate -L 4GiB -n chiwui-swap vg_ganeti
+        mkswap --uuid $SWAP_UUID /dev/vg_ganeti/chiwui-swap
 
  6. on the master, create the instance, adopting the LV: