scripts: in case of failed download, remove partial files

It happens from time to time that the server mis-behaves, and breaks the
connection right in the middle of nowhere, for no good reason, leaving us
with a partial file, on which the extract pass would choke.

Remove partial downloads, to fail early.

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

# Compute Blackfin-specific values

CT_DoArchTupleValues() {

    # The architecture part of the tuple:

    CT_TARGET_ARCH="bfin"

    # gcc ./configure flags

    CT_ARCH_WITH_ARCH=

    CT_ARCH_WITH_ABI=

    CT_ARCH_WITH_CPU=

    CT_ARCH_WITH_TUNE=

    CT_ARCH_WITH_FPU=

    CT_ARCH_WITH_FLOAT=

}