* configure.ac: learn to find polkit-dbus
    * src/oddjobd.c: model but don't check with PolicyKit in ACLs
    * src/oddjobd.conf.5.in: update to note that PolicyKit actions
    	can be (or will be able to be) used in ACLs.
    * doc/oddjob.xml.in: update to note the syntax for specifying a
    	PolicyKit action in an ACL entry