Create new interface and type for managing /etc/udev/rules.d
    
    udev_var_run_t is used for managing files in /etc/udev/rules.d as well as other files, including udev pid files.  This patch creates a type specifically for rules.d files, and an interface for managing them.  It also gives access to this type to initrc_t so that rules can be properly populated during startup.  This also fixes a problem on Gentoo where udev rules are NOT properly populated on startup.
    
    Signed-off-by: Chris Richards <gizmo@giz-works.com>
    Signed-off-by: Chris PeBenito <cpebenito@tresys.com>