More SELinux policy related changes.

* create a qmux_socket domain for talking with
  the qmuxd multiplexer.
* add a new domain for a shell that is started
  by init using a UID other than shell.

Change-Id: Idaaa1b8a36f6d8cd79f25fc66c59ede0bedd7900
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>