BUG: Manually download distribute required for SimpleITK

Download distribute version required by SimpleITK's build directory to
be automatically detected by distribute_setup.py. The distribute
download from pipy has moved to a https URL. SSL is not yet supported by
Slicer's version of python. So we moved the download to midas and
manually get it.

From: Bradley Lowekamp <blowekamp@mail.nih.gov>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22164 3bd1e089-480b-0410-8dfb-8563597acbee