Introduce asec_public_file type.

This new type will allow us to write finer-grained
policy concerning asec containers. Some files of
these containers need to be world readable.

Change-Id: Iefee74214d664acd262edecbb4f981d633ff96ce
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>
Merge remote-tracking branch 'cm/cm-11.0' into HEAD