Narrow permission re-granting to specific volume.

When mounting a storage volume after an SDK upgrade, the platform
grants install permissions requested by apps.  This patch fixes a
bug that was causing us to re-grant permissions for all installed
apps; we now narrow the granting to just the storage volume of
interest.

Also fixes a bug where scanning of internal ASECs would bump the
VersionInfo of the legacy apps-on-SD volume.

There is still a bug here around internal ASECs not being considered
for re-grants, but that needs to be fixed in a more invasive CL that
creates a separate VersionInfo.  In addition, internal ASECs (also
known as forward locked apps) have been deprecated for some time.

Bug: 24583803
Change-Id: I9115fd484ec083bc10a970f5f612860d5a53e520