verity: remove the depth parameter from bht_create

file_hasher.h

Index: file_hasher.h
diff --git a/file_hasher.h b/file_hasher.h
index ff1b03cff6b6fd6ddafdbce19577efe8535f45a3..2ff920b6d0a776d17132a77c8740c300c305d5a9 100644
--- a/file_hasher.h
+++ b/file_hasher.h
@@ -28,7 +28,6 @@ class FileHasher {
   virtual ~FileHasher() { dm_bht_destroy(&tree_); }
   virtual bool Initialize(simple_file::File *source,
                           simple_file::File *destination,
-                          unsigned int depth,
                           unsigned int blocks,
                           const char *alg);
   virtual bool Hash();
@@ -44,7 +43,6 @@ class FileHasher {
  private:
   simple_file::File *source_;
   simple_file::File *destination_;
-  unsigned int depth_;
   unsigned int block_limit_;
   const char *alg_;
   struct dm_bht tree_;