Use new setupAppDir() API for creating app-specific directories.

Use a more targeted API to create app-specific directories; allows us to
set the UID of app-specific directories correctly on devices that don't
have sdcardfs.

Bug: 146419093
Test: atest FuseDaemonHostTest
Test: boot device without FUSE, verify app dirs are created.
Change-Id: I40d9f95a0bf2e53cc6f80d46d46ef71fb39315be
2 files changed