fix. default for count arg.

Change-Id: I77b83b1f5e0a79e32b2d2b5fd22b5157df3bbe1f
fix. log_deploys, don't use logger to output.  Select the latest deploys to log.

Change-Id: Ia4186ed3202e14e83eafe87e8ef8502e2d461901
fixes. To diff and _get_commit_sha_for_tag.

Change-Id: I4af434c36069beb577cd78fe33ae2cff6c7958e1