Allow space in vbd path name

c/s 20393 breaks existing domain configuration that contains
spaces in the vbd path name.  Fixed by this trivial patch which
provides missing quotes.

Signed-off-by: Jim Fehlig <jfehlig@novell.com>
xen-unstable changeset:   21459:611a36481e92
xen-unstable date:        Wed May 26 08:14:51 2010 +0100

tools/hotplug/Linux/block

@@ -272,8 +272,8 @@ mount it read-write in a guest domain."
 
         if [ "x$mode" != 'x!' ]
         then
-          inode=$(stat -c '%i' $file)
-          dev=$(stat -c '%D' $file)
+          inode=$(stat -c '%i' "$file")
+          dev=$(stat -c '%D' "$file")
           if [ -z "$inode" ] || [ -z "$dev" ]
           then
             fatal "Unable to lookup $file: dev: $dev inode: $inode"