patch applied (cabal): extraArgs should override args in command lines

[Duncan Coutts]

Tue Jul 31 19:30:42 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * extraArgs should override args in command lines
  besides, the order was inconsistent within the same function between the
  UserSpecified and FoundOnSystem cases.

    M ./Distribution/Program.hs -1 +1