tree ba9242574c5e07f213e70151ab8d391c8a3362ea
parent bf341e33b3b6cc55139a84a4934bbf649e825581
author Sen Jiang <senj@google.com> 1458086961 -0700
committer Sen Jiang <senj@google.com> 1458261534 -0700

Use pre-generated ext image instead of create it on the fly.

mkfs.ext3 is not available in target device, so we don't use it.
Also removed all usage of dd.
This fixes a UtilsTest and the first step of integration test, the rest is
still failing because bsdiff is missing.

Test: ./update_engine_unittests
Test: cros_workon_make update_engine --test
Bug: 26955860

Change-Id: Ic600bd6fab1d6839f38d5ef767fbffc5a35571a4