Allow PMS to restorecon directories under /data.

This change applies a relabel to both /data/data and
/data/user directories on boot. Not every boot will
apply this relabeling however. The appropriate
seapp_contexts is hashed and compared to
/data/system/seapp_hash to decide if the relabel
should occur.

Change-Id: I05e8b438950ddb908e46c9168ea6ee601e6d674f
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>