patch applied (cabal-install): Use user installs by default

[Simon Marlow]

Duncan Coutts wrote:
> Fri May  4 03:46:52 PDT 2007  Duncan Coutts <duncan.coutts at worc.ox.ac.uk>
>   * Use user installs by default
>   So it "Just Works"tm without needing extra options or sudo fiddling.
>   If you care you can still do sudo fiddling and --global-install

This is inconsistent with Cabal and ghc-pkg, which both use global installs by 
default.  At the time we felt that global installs were the more common case.  I 
know this isn't a clear-cut issue though, and there are good arguments on both 
sides.  For example, one could argue that only the system's package manager 
should install packages globally, so since we're bypassing the system package 
manager we should default to user installs.

However, I'm more concerned that we are consistent, and avoid surprising 
behaviour where possible.

Cheers,
	Simon