Fix segfault that might occur when performing a rollback from a snapshot that
isn't made into an EVMS volume.

Apply with:
cd /usr/src/evms-2.5.1
patch -p1 < snapshot.c.patch
make
make install

--- evms-2.5.1a/plugins/snapshot/snapshot.c	20 Dec 2004 20:58:59 -0000
+++ evms-2.5.1b/plugins/snapshot/snapshot.c	9 Feb 2005 21:20:37 -0000
@@ -1425,7 +1425,7 @@
 			   "volume will be lost. Both the snapshot "
 			   "and the origin volumes must remain un-"
 			   "mounted until the rollback is complete.\n"),
-			 object->volume->name,
+			 object->name,
 			 volume->origin->parent->volume->name);
 		if (answer != 0) {
 			rc = E_CANCELED;