Touch blocks in care_map in update_verifier

Read all blocks in system and vendor partition during boot time
so that dm-verity could verify this partition is properly flashed.

Bug: 27175949
Change-Id: I38ff7b18ee4f2733e639b89633d36f5ed551c989
Test: mma
(cherry picked from commit 03ca853a)
(cherry picked from commit 4bbe0c93)
(Fix a typo when comparing the verity mode)
(cherry picked from commit da654af6)
(Skip update verification if care_map is not found)