libceph: fix crush_decode() for older maps

Older (shorter) CRUSH maps too need to be finalized.

Fixes: 66a0e2d5 ("crush: remove mutable part of CRUSH map")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

net/ceph/osdmap.c

@@ -390,9 +390,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
 	dout("crush decode tunable chooseleaf_stable = %d\n",
 	     c->chooseleaf_stable);
 
-	crush_finalize(c);
-
 done:
+	crush_finalize(c);
 	dout("crush_decode success\n");
 	return c;