scripts/functions: force extract folder to archive basename

Some archives like those of the 2011.07 revisions of Linaro GCC contain a folder
name different from the archive basename, which leads to errors afterwards, e.g.
when patching. E.g.:
gcc-linaro-4.5-2011.07.tar.bz2 extracts to gcc-linaro-4.5-2011.07-0/

This patch changes CT_Extract() to force the extraction of all archives to a
folder named like the archive basename. E.g.:
gcc-linaro-4.5-2011.07.tar.bz2 now extracts to gcc-linaro-4.5-2011.07/

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

 # Overall toolchain configuration: paths, jobs, etc...

 # Allow unconditional usage of tristates

 config MODULES

     bool

     default y

 menu "Paths and misc options"

 source "config/global/ct-behave.in"

 source "config/global/paths.in"

 source "config/global/download.in"

 source "config/global/extract.in"

 source "config/global/build-behave.in"

 source "config/global/logging.in"

 endmenu