Revert "Break metadata into smaller chunks (number of chunks=10) for faster delta generation."
Revert "Break metadata into smaller chunks (number of chunks=10) for faster delta generation."

This reverts commit 4e8a306bb126b80e1d64a5e799a14e8aa6b55762.

BUG=chromium-os:10669
TEST=Unit tests

Review URL: http://codereview.chromium.org/6014014

Change-Id: Id582cbb6f1289dde119eff9f18ea78d350cd21ab

mjg59/update_engine,endocode/update_engine,marineam/update_engine,mjg59/update_engine,endocode/update_engine,marineam/update_engine,mjg59/update_engine,marineam/update_engine,endocode/update_engine,marineam/update_engine