colo: examples: remove mentions of script= and (wrong) downscript=

colo: examples: remove mentions of script= and (wrong) downscript=

There's no need to repeat script=/etc/qemu-ifup in examples,
as it is already in there.  More, all examples uses incorrect
"down script=" (which should be "downscript=").

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>