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>

# Compute Alpha-specific values

CT_DoArchTupleValues () {

    # The architecture part of the tuple:

    CT_TARGET_ARCH="${CT_ARCH}${CT_ARCH_ALPHA_VARIANT}"

}