vmdk: remove unneeded variable assignment

Spotted by Clang Analyzer

Signed-off-by: Pavel Borzenkov <pavel.borzenkov@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/block/vmdk.c b/block/vmdk.c
index 5d16ec4..3969131 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1387,7 +1387,6 @@
             bdrv_delete(bs);
             return -EINVAL;
         }
-        filesize = bdrv_getlength(bs);
         parent_cid = vmdk_read_cid(bs, 0);
         bdrv_delete(bs);
         relative_path(parent_filename, sizeof(parent_filename),