scripts: fix broken variable name

This patch fixes a config variable name missing its 'CT_' prefix.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

reporter_name="Ioannis E. Venetis"

reporter_url="http://sourceware.org/ml/crossgcc/2011-05/msg00005.html"

reporter_comment=""