scripts: fix download from sourceforge

It seems sourceforge changed yet again the way to download files.
This time, no longer use their 'mesh' thingy, and hard-code the
server to use in the URL... Sigh... :-(

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

reporter_name="Kevin Cernekee"

reporter_url="http://sourceware.org/ml/crossgcc/2011-09/msg00037.html"

reporter_comment="MIPS SDE-compatible toolchain"