Add BOARD_ODM_SEPOLICY_DIRS to neverallow checks.

It doesn't seem like any of our (Google's) devices use
BOARD_ODM_SEPOLICY_DIRS, but this will be helpful for partners.

Also, use BOARD_VENDOR_SEPOLICY_DIRS instead BOARD_SEPOLICY_DIRS for
readability.

Bug: n/a
Test: m selinux_policy
Change-Id: I23f64a24d51ccdb8aa616d0fd8a06d70b6efed32