XMonad.Actions.PhysicalScreens: fix typo spotted by Chris Pick <haskell@chrispick.com>
XMonad.Actions.PhysicalScreens: fix typo spotted by Chris Pick <haskell@chrispick.com>

Ignore-this: eb73b33b07dc58a36d3aa00bc8ac31c2

darcs-hash:20120115223013-f7719-4228a5965af6cfa3a770103ee4d856df3f7540cc

yzhou61/xmonad-contrib,yzhou61/xmonad-contrib,yzhou61/xmonad-contrib