patch applied (cabal): Change --configure-option= to --configure-arg=

[Duncan Coutts]

Sat Sep  1 17:33:34 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * Change --configure-option= to --configure-arg=
  For consitency with other flags.

    M ./Distribution/Simple/Setup.hs -3 +3
    M ./doc/Cabal.xml -2 +2