pip install --user rootpy fails due to distribute dependency

I just tried installing rootpy to my user directory, to no avail. I think we should try and support this where possible.

The problem is that for some reason our installation has a dependency on recent distribute (more recent than my gentoo distribution has built in). Can someone take a look at this? I can provide access to machine if necessary.

Is such a dependency really necessary? It seems like we should be able to support slightly older versions of distribute. Unfortunately `pip install --user -U distribute` fails because it tries to remove the installed system distribute version.

I currently get:

	Downloading/unpacking rootpy
	  Downloading rootpy-0.7.0.tar.gz (307kB): 307kB downloaded
	  Running setup.py egg_info for package rootpy
	    The required version of distribute (>=0.6.32) is not available,
	    and can't be installed while this script is running. Please
	    install a more recent version first, using
	    'easy_install -U distribute'.
	    
	    (Currently using distribute 0.6.30 (/usr/lib64/python2.7/site-packages/distribute-0.6.30-py2.7.egg))
	    Complete output from command python setup.py egg_info:
	    The required version of distribute (>=0.6.32) is not available,

	and can't be installed while this script is running. Please

	install a more recent version first, using

	'easy_install -U distribute'.