Handle vdevs with full paths

Index: grub/util/getroot.c
===================================================================
--- grub.orig/util/getroot.c	2012-02-03 05:22:36.227364000 -0600
+++ grub/util/getroot.c	2012-02-03 05:22:41.255135000 -0600
@@ -301,7 +301,10 @@
 		    devices = xrealloc (devices, sizeof (devices[0])
 					* devices_allocated);
 		  }
-		devices[ndevices++] = xasprintf ("/dev/%s", name);
+		if (name[0] == '/')
+		  devices[ndevices++] = xstrdup (name);
+		else
+		  devices[ndevices++] = xasprintf ("/dev/%s", name);
 	      }
 	    break;
 	  }