Higher upper bounds for GHC 7 support

The following reddit thread: http://www.reddit.com/r/haskell/comments/e6o0y/ghc_701_released/c15s7rj brought up some problems building cabal-install with GHC 7. I think increasing the upper bounds on Cabal and cabal-install as below will get them to compile with GHC 7. Cabal: filepath 1.2 directory 1.1 containers 0.4 cabal-install: time 1.2