ifdef RACCT ui_racct_foreach and struct uidinfo's ui_racct

Change racct_ create and destroy to macros evaluating to nothing without RACCT
so that their callers passing ui_racct don't have to be ifdefed.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274911 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f