Add seinfo parsing to PackageManagerService.

This patch set allows the PMS to parse the
mac_permissions.xml file which contains the
seinfo values. Each package that is installed
on the device will be assigned an seinfo value
based on policy. This seinfo value will help label
the app process and data directory.  Modifications
include adjustments to ApplicationInfo.java
to store the seinfo tag per package as well as
adjustments to installd to communicate the seinfo
tag to libselinux.

Change-Id: I61ad1ea12fb6a9a6d0b108ec163bc4bf4c954b58
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>