portage-conf/default/package.use/x: Re-break pambase <-> consolekit loop

portage-conf/default/package.use/x: Re-break pambase <-> consolekit loop

I's disabled consolekit for pambase in package.use/circular, but this
was re-enabling it (and package.use/x is parsed after
package.use/circular).  This dependency cycle broke the stage3 build,
but was, apparently, needed for some later stage.  If this fix doesn't
work, we can transition to using different portage-conf subdirectories
for different stages.