scripts: do not allow commas in directories, it breaks things

The comma is used by the autotools as separator in many sed expressions,
which break if a directory contains commas.

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

 reporter_name="Remy Bohmer"

 reporter_url="linux@bohmer.net"

 reporter_comment="Example for building a toolchain for m68000 bare metal targets"