There's a naming convention between the testcase and the class/method
being tested.
Also remove VerifiedBootVersion2HashtreeInfoGenerator as it's merely a
placeholder without telling anything much (e.g. whether it's to be
implemented or working as intended).
Test: python -m unittest test_verity_utils
Change-Id: Ieb156765c865aa551e3882f381e3a6db2cac4cbc
Generate the transfer command "compute_hash_tree" for incremental
updates of the non-A/B devices that enable verified boot 1.0
Other changes include:
i. factor out verity_utils to use both in build_image and blockimgdiff
ii. add a new flag 'hashtree_info_generator' in sparse_image to generate
the hashtree information.
Bug: 25170618
Test: generate a package for aosp_angler; and run simulator
Change-Id: I4d4d7a3e41dc3da810d2cbf8988e85d187c9ab0e
