vdi: Fix memory leak

The block map is allocated in vdi_open, but was never freed.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/vdi.c b/block/vdi.c
index 7dda522..02da6b4 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -949,6 +949,9 @@
 static void vdi_close(BlockDriverState *bs)
 {
     BDRVVdiState *s = bs->opaque;
+
+    g_free(s->bmap);
+
     migrate_del_blocker(s->migration_blocker);
     error_free(s->migration_blocker);
 }