Remove garbage spaces
doc: follow download URL change on SF.net

http://downloads.sourceforge.net/project/cutter/cutter-1.2.2.tar.gz ->
http://downloads.sourceforge.net/        cutter/cutter-1.2.2.tar.gz
                                 ^^^^^^^^

"project/" is removed.

[cutter-users-ja:91]

Reported by Siganai SE. Thanks!!!