verity: move metadata after the hash tree

Move the verity metadata block after the hash tree to make locating
it easier and more reliable.

Needs matching changes from
  I6945cbab99e214566a1f9d3702333f2dbbc35816

Change-Id: Ide48f581bbba77aed6132f77b309db71630d81ed
diff --git a/verity/build_verity_metadata.py b/verity/build_verity_metadata.py
index 547e606..51e629a 100755
--- a/verity/build_verity_metadata.py
+++ b/verity/build_verity_metadata.py
@@ -44,7 +44,7 @@
                 BLOCK_SIZE,
                 BLOCK_SIZE,
                 data_blocks,
-                data_blocks + (METADATA_SIZE / BLOCK_SIZE),
+                data_blocks,
                 root_hash,
                 salt)
     return table